The atom is a complex system. Presentation on theme: "The atom is a complex particle." Determination of the number of electrons, protons, neutrons in an atom
Atom -
complex particle
"Everything around
us consists of
indivisible particles
or atoms"
Democritus
(about 460 BC -
around 360 BC e.)
X-rays
Crystal
Diffractive
picture
Wilhelm Conrad Roentgen
German physicist
In 1895
University of Würzburg
Electrons
In 1897
John Thomson
English physicist
Cambridge university
Antoine Henri Becquerel
French physicist
1896
The phenomenon of radioactivity
blackening
Manifested
photographic plate
Uranium salts
Maria Sklodowska-Curie
Pierre Curie
Polish physical chemist
French physical chemist
In 1903
Discovery of radium
Opening
polonium
"Pudding Model"
John Thomson
English physicist
In 1904
Electrons make oscillatory motions, due to which the atom emits electromagnetic energy, and the atom itself is electrically neutral.
Ernest Rutherford
English physicist
Scattering of an α-particle
In 1907
"Planetary Model"
Quantum theory
Niels Bohr
Danish physicist
Electrons move in closed orbits in accordance with the value of their energy, which is not released or absorbed at the same time.
In 1913
An electron can move from one allowed energy state to another, emitting or absorbing energy in the process.
Dmitry Dmitrievich
Werner Karl
Ivanenko
Heisenberg
Russian physicist
German theoretical physicist
In 1932
Nucleons = Protons (Z)+ Neutrons (N)
Proton - neutron
theory
A is the mass number of the atom
are types of chemical atoms
isotopes
elements that have the same
atomic number, but different mass numbers.
Number of electrons
Core charge
Number of protons (Z)
Serial number
Electron
Mass
Protons
Electrons
A change in the number of protons in an atom leads to the formation of a new chemical element, because the charge of the atom's nucleus changes.
1 proton (Z)
1 proton (Z)
A change in the number of neutrons in an atom leads to a change in the atomic mass of the element.
Isotopes of hydrogen differ in their properties.
Deuterium
An element is a collection of atoms with the same nuclear charge.
Oxygen
free atoms
Simple substances
oxygen
ozone
Complex Substances
CH₃ - O - CH₃
С₂Н ₅ - OH
ethanol
dimethyl ether
We learned about the contribution of scientists from all over the world to the development of the theory of the structure of the atom;
Explained the existence of isotopes on the example of hydrogen;
Considered the elementary composition of the atom on the example of phosphorus.
Sulfur chemical element- (Soufre French, Sulfur or Brimstone English, Schwefel German, θετον Greek, Latin Sulfur, whence the symbol S; atomic weight 32.06 at O=16 [Determined by Stas from the composition of silver sulfide Ag 2 S]) belongs among the most important non-metallic elements.
Sulfur, chemical element- (Soufre French, Sulphur or Brimstone English, Schwefel German, θετον Greek, Latin Sulfur, whence the symbol S; atomic weight 32.06 at O=16 [Determined by Stas from the composition of silver sulfide Ag2S]) belongs to the number the most important non-metallic elements. She is… … Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
Compression in chemical reactions- In a large number of cases, chemical reactions are accompanied by a change in the volume of substances involved in the transformation. In the case when the volume of substances entering the reaction is greater than the volume of substances occurring during the reaction, a positive C is observed. ... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
Complex compounds- Cis platinum is one of many coordination compounds Complex compounds (Latin complexus combination, girth) or coordination compounds (l ... Wikipedia
Substance as matter- (Matière, Substance, Materie, Stoff, Matter) is opposed in meaning to spirit, force, form, appearance and emptiness. Such a negative definition, originating from antiquity, cannot serve as a basis for any scientific information about V. Science, however ... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
Fermentation (chemical process)- represents a special chemical process caused by the so-called. enzymes. During the process of fermentation, a complex particle of organic matter decomposes into simpler ones, i.e., containing a smaller number of atoms. Among the huge number of fermentations, as ... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
Fermentation- (chemical process) is a special chemical process caused by the so-called. enzymes. During the process of fermentation, a complex particle of organic matter decomposes into simpler ones, i.e., containing a smaller number of atoms. Among the vast number ... ... Encyclopedic Dictionary F.A. Brockhaus and I.A. Efron
Fermentation- represents a special chemical process caused by so-called enzymes. During the fermentation process, a complex particle of organic matter breaks down into simpler ones, i.e. containing a smaller number of atoms. Among the huge number of fermentations, like ... ... Encyclopedia of Brockhaus and Efron
complex particle- sudėtingoji dalelė statusas T sritis fizika atitikmenys: engl. complex particle vok. zusammengesetztes Teilchen, n rus. complex particle, f pranc. particule constituante, f … Fizikos terminų žodynas
particle constituante- sudėtingoji dalelė statusas T sritis fizika atitikmenys: engl. complex particle vok. zusammengesetztes Teilchen, n rus. complex particle, f pranc. particule constituante, f … Fizikos terminų žodynas
Lesson 1. An atom is a complex particle Purpose: to summarize knowledge from physics and chemistry courses about phenomena that prove the complexity of the structure of the atom, to acquaint students with the evolution of scientific views on the structure of the atom. Know: features of the structure of the atom. Be able to: describe the structure of an atom, characterize the particles that make up its composition. Lesson progress Conversation: you remember that “atom” in Greek means “indivisible”, until the end of the 19th century this was considered true. But the discovery of the late nineteenth - early twentieth centuries. showed that the atom is complex. Lecture: Since it became clear that the atom consists of smaller particles, scientists have tried to explain the structure of the atom, proposed models: 1. J. Thomson (1903) - the atom consists of a positive charge, evenly distributed throughout the volume of the atom , and electrons oscillating inside this charge. This model has not been experimentally confirmed. 2. E. Rutherford (1911) - planetary or nuclear model of the atom: - inside the atom there is a positively charged nucleus, which occupies an insignificant part of the volume of the atom; - all the positive charge and almost all the mass of the atom is concentrated in the nucleus; - Electrons revolve around the nucleus, they neutralize the charge of the nucleus. Rutherford's model was confirmed by experiments with thin metal plates irradiated with alpha particles. But classical mechanics couldn't explain why the electrons don't lose energy as they spin and fall into the nucleus. 3. In 1913, N. Bohr supplemented the planetary model with postulates: - electrons in an atom rotate in strictly defined closed orbits, neither emitting nor absorbing energy; When electrons move from one orbit to another, energy is absorbed or released. 4. Modern quantum model of the structure of the atom: - the electron has a dual nature. Like a particle, an electron has a mass of 9.1x10-28g and a charge of 1.6x10-19C. - an electron in an atom does not move along a certain trajectory, but can be located in any part of the nuclear space. The probability of finding an electron in different parts of the circumnuclear space is not the same. The space around the nucleus where the probability of finding an electron is greatest is called the orbital. - The nucleus consists of nucleons - protons and neutrons. The number of protons in the nucleus is equal to the atomic number of the element, and the sum of the numbers of protons and neutrons is equal to the mass number of the atom. This provision was formulated after the discovery by E. Rutherford in 1920 of the proton, and by J. Chadwick in 1932 of the neutron. Different kinds of atoms are called nuclides. Nuclides are characterized by mass number A and nuclear charge Z. Nuclides with the same Z but different A are called isotopes. (35 17Cl and 37 17Cl). Nuclides with different Z, but the same A are called isobars. (40 18Ar and 40 19K). Task 1: - paint the structure of the atom for the elements: iron, aluminum, barium, potassium, silicon. Task 2 1. Determine the chemical element by the composition of its atom - 18 p+, 20 n0, 18 e-: a) F b) Ca c) Ar d) Sr 2. The total number of electrons in the chromium ion 24Cr3+: a) 21 b) 24 c) 27 d) 52 3. The maximum number of electrons occupying the 3s orbital is: a) 14 b) 2 c) 10 d) 6 4. The number of orbitals on the f - sublevel: a) 1 b) 3 c) 5 g ) 7 5. The smallest atomic radius among the given elements has: a) Mg b) Ca c) Si d) Cl Homework: § 1. learn from a notebook, tasks 1-4.
MKOU
them. G. G. Gyulmagomedova
Made by 11th grade student
Ibragimova Arina
Supervisor
Vezirov T. G.
Arak 2014
HOW DEVELOPED THE CLASSICAL THEORY OF THE STRUCTURE OF THE ATOM? 3
Thomson Model 4
Rutherford Experience 5
Quantum postulates of N. Bohr 6
The state of an electron in an atom 6
Types of orbitals: 7
Atomic nucleus 8
Isotopes 10
Isotope properties: 11
Determination of the number of electrons, protons, neutrons in an atom. 12
Distribution of electrons by energy levels. 12
Atom is a complex particle
Atom – an electrically neutral system of interacting elementary particles, consisting of a nucleus (formed by protons and neutrons) and electrons.
Absolute masses of atoms (masses expressed in kilograms): from 10 -27 before10 -25 kg.
Atom diameters: from 1,06 *10 -10 before 2*10 -10 m.
For example : m a (H)= 1.67*10 -27 kg.
d a (H) \u003d 1.06 * 10 -10 m
The concept of an atom came to us from distant antiquity, but completely changed the original meaning that the ancient Greeks put into it. Translated from Greek "atom" means "indivisible" .
The essence of the structure of the atom was proved by fundamental discoveries made at the end of the 19th and beginning of the 20th centuries. as a result of the study of the nature of cathode rays by J. Thomson in 1897, the discovery of the phenomenon of the photoelectric effect by A. G. Stoletov in 1889, the discovery of the radioactivity of chemical elements by A. Becquerel in 1896 1899, the definition of nature α - particles E. Rutherford in 1889 - 1900.
Scientists came to the conclusion that atoms have their own structure, have a complex structure.
HOW DEVELOPED THE CLASSICAL THEORY OF THE STRUCTURE OF THE ATOM?
The electron rotates around the nucleus in strictly defined closed stationary orbits in accordance with the "allowed" energy values E 1 , E 2 , ..., E n
2 postulate
An electron passes from one "allowed" energy state to another, which is accompanied by the emission or absorption of an energy quantum.
The state of an electron in an atom
Under the state of an electron in an atom understand the totality of information about the energy of a particular electron and the space in which it is located. We already know that an electron in an atom does not have a trajectory of motion, that is, we can only talk about the probability of finding it in the space around the nucleus.O 
n can be located in any part of this space surrounding the nucleus, and the totality of its various positions is considered as electron cloud with a certain negative charge density.
Figuratively, this can be represented as
The space around an atomic nucleus
which is most likely to be found
electron, is called orbital
.
Types of orbitals:
Integer n, denoting the energy level number, is called principal quantum number. It characterizes the energy of electrons occupying a given energy level. The electrons of the 1st energy level, closest to the nucleus, have the lowest energy. Compared with the electrons of the 1st level, the electrons of the next levels will be characterized by a large amount of energy. Consequently, the electrons of the outer level are the least strongly connected with the nucleus of the atom.
The number of energy levels (electronic layers) in an atom is equal to the number of the period in the system of D. I. Mendeleev, to which the chemical element belongs: the atom of the elements of the 1st period has one energy level, the second period has two, the seventh period has seven.
The largest number of electrons in the energy level is determined by the formula:
N \u003d 2 n 2,
where N is the maximum number of electrons; n is the level number or the main quantum number. Consequently, the first energy level closest to the nucleus can contain no more than two electrons;
on the second - no more than 8;
on the third - no more than 18;
on the fourth - no more than 32.
The number of sublevels is equal to the value of the main quantum number: the first energy level has one sublevel; the second - two; third - three; the fourth - four sublevels. The sublevels, in turn, are formed by orbitals.
s – Sublevel - the first sublevel of each energy level, closest to the nucleus of an atom, consists of one s - orbitals;
p – Sublevel - the second sublevel of each, except for the first, energy level, consists of three p – orbitals ;
d – Sublevel - the third sublevel of each, starting from the third, energy level, consists of five d – orbitals
f
– Sublevel
each, starting from the fourth, energy level, consists of seven f
– orbitals
.
atom nucleus
But not only electrons are part of atoms.Physicist Henri Becquerel discovered that a natural mineral containing uranium salt also emits unknown radiation, illuminating from light. This phenomenon has been called radioactivity .
There are three types of radioactive rays:
α - rays, which consist of α - particles having a charge 2 times the charge of an electron, but with a positive sign, and a mass 4 times more than a hydrogen atom;
β - rays represent a stream of electrons;
γ - rays - electromagnetic waves with a negligible mass that do not carry an electric charge.
It turns out that the tiny nucleus itself, in which the entire mass of the atom is concentrated, consists of particles of two types - protons andneutrons.
Protons have a charge equal to the charge of electrons, but opposite in sign (+1), and a mass equal to the mass of a hydrogen atom (it is accepted in chemistry as a unit). Protons are denoted by the sign R + .
Neutrons do not carry a charge, they are neutral and have a mass equal to the mass of a proton, i.e. 1. Designate neutrons n 0 .
Protons and neutrons are collectively called nucleons(from lat. nucleus- nucleus).
The sum of the number of protons and neutrons in an atom is called mass number. For example, the mass number of an atom aluminum (Al) :
number of protons
Mass number
number of neutrons
13 + 14 = 27
Since the atom is electrically neutral, it is also obvious that the number of protons and electrons in the atom is the same. It is equal to the serial number of the chemical element. And knowing the serial number of the element (Z), i.e. the number of protons, and the mass number (A), equal to the sum of the numbers of protons and neutrons, can be found by the formula:
N P+
n 0
e-
particle
location
weight
charge
Proton
nucleus
1 amu
+1
Neutron
nucleus
1a.u.m.
0
Electron
orbital
0
-1
A-Z
isotopes
Varieties of atoms of the same element that have the same nuclear charge but different mass numbers are called isotopes.Word isotope consists of two Greek words: isos is the same, and topos- place, means "occupying one place" (cell) in the Periodic system of elements.
Chemical elements found in nature are a mixture of isotopes. So, carbon has three isotopes with a mass of 12, 13, 14; oxygen - three isotopes with a mass of 16, 17, 18, etc.
However, hydrogen isotopes differ greatly in properties due to
a multiple increase in their relative mass; they were even given
individual names and chemical symbols:
Properties of isotopes:
So, isotopes tend to:
Table of contents
Determination of the number of electrons, protons, neutrons in an atom.
Legend:
X is the symbol for a chemical element
Z is the serial number of the chemical element
A - atomic mass
The number of electrons and protons is equal to the serial number of the chemical element
The number of neutrons is equal to the difference
Example: Determine the number of particles in the following atoms:
Hydrogen. Ordinal number in the periodic table D.I. hydrogen has 1, atomic mass 1, therefore electrons and protons in an atom one at a time, and neutrons 1-1=0.
Lithium. Ordinal number 3, and atomic mass 7, therefore electrons and protons 3 each, and neutrons 7-3=4.
Distribution of electrons by energy levels.
Electrons in atoms have different amounts of energy. The value of the energy of electrons in atoms is given by the main quantum number n (1,2,3, etc.). The lowest energy electrons are in the first energy level. Each level is divided into sub-levels - orbitals. Each orbital cannot have more than 2 electrons.
Types of electron clouds:
- a cloud of spherical shape (s-cloud)
- dumbbell-shaped clouds (p-cloud)
-clouds of a more complex shape (d- and f-clouds)
[Arak secondary school] [Ibragimova A.]
Atom is a complex particle
Lesson Objectives: to summarize information about the most important discoveries in physics of the 19th-20th centuries, proving the complexity of the structure of atoms of chemical elements; teach to explain the structure of the atom, based on some models of classical theory; consolidate knowledge of modern ideas about the structure of the atom based on quantum mechanics.
Basic concepts: macrocosm, microcosm, quantum mechanics, nucleons (protons, neutrons), nuclides, isotopes, corpuscular-wave dualism of microcosm particles, chemical element.
Equipment: PSCE D. I. Mendeleev, tables "Structure of the atom".
During the classes
I. Organizational moment
Teacher greeting. Check readiness for the lesson.
II. Learning new material
Presentation plan
1. The most important discoveries in physics of the late XIX-early XX century.
2. Models of the classical theory of the structure of the atom, an explanation of their failure.
3. Modern ideas about the structure of the atom based on quantum mechanics. Proton-neutron theory.
4. Nuclides are different types of atoms. Isotopes. Isotopes of hydrogen.
5. Forms of existence of a chemical element.
1. It is advisable to read the first paragraph of the plan on p. 3 textbooks the concept of "atom", fundamental discoveries that prove the complexity of the structure of the atom, followed by writing in a workbook.
In 1904 J. Thomson proposes a model of the atom called"plum pudding" The atom as a whole is electrically neutral, since it is like a spherical drop of pudding with a positive charge, inside the sphere of which negatively charged electrons are interspersed, making oscillatory movements, due to which the atom radiates electromagnetic energy. However, this model was not experimentally confirmed and remained a hypothesis.
In 1911 E. Rutherford offersplanetary model atom. Like the motion of the planets in closed orbits around the Sun, the model of an atom is a positively charged nucleus and electrons revolving around the nucleus in closed stationary orbits. However, this model could not explain the phenomena of radiation and absorption of energy by an atom.E. Rutherford is considered the founder of the modern theory of the atom, we still use his theoretical model of the structure of the atom.
In 1900 M. Planck, in 1905 A. Einstein and N. Bohr introduced theoretical ideas and quantum concepts into E. Rutherford's planetary model -postulates (postulate is a statement accepted without proof).
First postulate: an electron can revolve around the nucleus not in any, but only in certain certain circular orbits. These orbits are called stationary. In this case, energy is neither absorbed nor emitted by the atom.
Second postulate: the emission or absorption of energy by an atom occurs when an electron jumps from one stationary orbit to another. In this case, a separate portion of energy - a quantum - is emitted or absorbed.
N Bor introduced quantum ideas about the structure of the atom, but he used the traditional classical concepts of mechanics,considering an electron as a particle moving with strictly defined velocities along strictly defined trajectories. His theory was an important stage in the development of ideas about the structure of the atom.
The hypothesis proposed by M. Planck and A. Einstein about light quanta (photons) shows that it is impossible to automatically extend the laws of nature, which are valid for most bodies - objects of the macrocosm, to negligibly small objects - the microcosm (atoms, electrons, etc.)
In the 1920s, after the emergence and development of a new branch of theoretical physics - quantum or wave mechanics - the problem of describing the properties and behavior of microworld particles was solved. This theory characterizes particles of the microcosm as objects with a dual nature - corpuscular-wave dualism: at the same time they are both particles (corpuscles) and waves. The corpuscular-wave dualism of objects of the microworld is also confirmed experimentally by the interference and diffraction of electrons, which are experimentally familiar from the course of physics. Interference is the superposition of waves on each other. Diffraction is the wave bending around an obstacle. This proves the existence of v electron wave properties. The blackening of the photolayer in only one place indicates the presence of corpuscular properties in it. If the electron were only a wave, it would illuminate the photographic plate more or less uniformly (Fig. 1 p. 5 of the textbook).
In 1932, the proton-neutron theory of the nucleus was developed , according to which the nuclei of atoms consist of protons with charge +1 and mass 1, and neutrons with charge 0 and mass 1. They are called nucleons.
An atom is an electrically neutral system of interacting elementary particles, consisting of a nucleus (formed by protons and neutrons) and electrons.
The serial number of the element in the PSCE D.I. Mendeleev corresponds to the charge of the nucleus of an atom, that is, indicates the number of protons in it. The number of neutrons is determined by the formulaN=A-Z , where A is the mass number, Z is the ordinal number of the element. The number of electrons in an atom corresponds to the serial number of the element in the PSCE.
Example: The element's serial number is 25. The mass number is 55. What is the composition of its atom?
Answer: The charge of the nucleus of an atom is +25; in the nucleus of an atom there are 25 protons, neutrons 55 - 25 = 30; There are 25 electrons in an atom.
Question: What should be expected if the number of a) protons in an atom is changed; b) neutrons?
Answer: A change in the number of protons in an atom leads to the formation of a new chemical element. the charge of the nucleus of an atom changes.
A change in the number of neutrons in an atom leads to a change in the atomic mass of the element, the charge of the atomic nucleus does not change. Are formedisotopes - varieties of atoms of the same element that have the same nuclear charge, but different relative atomic mass.
Example: Isotopes of chlorine: +17 Сl, at. weight 35, and +17 Сl, at. weight 37; potassium isotopes +19 K, at. weight 39, and +19 K, at. weight 40.
The properties of isotopes of the same element are the same, because they have the same nuclear charge, although their relative atomic mass is different, because. they contain different numbers of neutrons; the change in the atomic mass of the elements is insignificant - it has a fractional value.
Hydrogen isotopes have their own names and chemical symbols:
Protium - H - has a nuclear charge of +1 and an atom mass of 1, there are no neutrons in the nucleus.
Deuterium - D - has an atomic nuclear charge +1 and an atom mass of 2, neutrons in the nucleus - I.
Tritium - T has an atomic nuclear charge of +1 and an atom mass of 3, neutrons in the nucleus - 2.
Question: Why do hydrogen isotopes differ significantly in properties?
Answer: Hydrogen isotopes have a very significant change in mass - by a multiple of times.
Based on the foregoing, a modern interpretation of the chemical element should be given.
A chemical element is a collection of atoms with the same nuclear charge, that is, with the same number of protons in it.
The following forms (methods) of the existence of a chemical element are known: free atoms, simple substances, complex substances.
Example: Hydrogen can exist in the form of free atoms, in the form of diatomic molecules, and also be part of the molecules of a complex substance.
Relationship between content and form on the example of three forms of existence of a chemical element
Simple substancesthe same chemical element
Various simple substances
Allotropes
Allotropes: oxygen - O 2 and O 3 - ozone
Complex Substances
Same composition (molecular formula)
Various complex substances
Isomers
FROM 2 H 6 O - corresponds to compounds: alcohol C 2 H 5 OH and ether H 3 C-O-CH 3
Conclusion: content and form are interconnected. The decisive role is given to the content (the charge of the atomic nucleus, the composition of simple and complex substances), but the form is not passive, it affects the content (isotopes, allotropes, isomers).
III. Consolidation on the key issues of the topic
Work with questions No. 1, 2, 3, 4 § 1.
Students read out the question of the paragraph and give an answer to it according to the summary in the workbook or according to the text of the textbook.
IV. Homework
§one. Determine the composition of atoms No. 13, No. 56, No. 30, No. 101
Answer the question of how argon atoms with masses 39 and 40 are similar and how they are different.
