Atomic structure Flashcards

1
Q

What is atom?

A

Atoms are smallest particles of matter

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2
Q

What is an element?

A

An element is made up of one kind of atom and that cannot be broken down into other substances chemical reactions

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3
Q

Do artificial elements are stable?

A

No,30 artificial are produced in lab and they are very unstable

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4
Q

What can we know from the columns of periodic table?

A

Groups of the elements with same properties as well as the valence electrons

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5
Q

What can we know from the rows of periodic table?

A

Periods(i.e.energy shells)

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6
Q

Sub atomic particles of atom

A

Atom contains nucleus.Protons and neutrons are inside the nucleus.A cloud of electrons are move around the nucleus.

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7
Q

How subatomic particles are measured?

A

Atomic mass unit

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8
Q

Charge of subatomic particles

A

Proton-positive charge (+1)
Neutron-neutral
Electron-negative charge(-1)

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9
Q

What are isotopes?

A

Atoms of the same element with different numbers of neutrons

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10
Q

Some isotopes are radioactive,what does it means?

A

Radioactive isotopes contain the nucleus that are unstable and giving out particle and energy when decays.

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11
Q

What is electron shell?

A

Electrons are arranged in shells around nucleus.

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12
Q

The energy of the 1st shell

A

Since it is the closest to the nucleus and it has lowest energy level

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13
Q

How electrons are arranged in first 3 shells?

A

The 1st shell can hold only 2e and it fills first.
The 2nd shell can hold 8e and it fills second.
The 3rd shell can hold 18e but it fills up to 8 and the next 2 go to 4th shell finally the rest are filled to 3rd shell.

288

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14
Q

Why group 0 are unreactive?

A

B/c they have very stable arrangement of electrons (no valence shell)

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15
Q

Properties of metals

A

1)Good conductor of heat and electricity
2)high melting point and boiling point i.e.solid at room temperature except mercury
3)hard,strong except Na,K
4)ductile,malleable
5)shiny
6)high density or heavy
7)form positive ions when react
8)react with oxygen to form basic oxides

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16
Q

Properties of nonmetal

A

1)Poor conductor of heat and electricity
2)low melting point and boiling point i.e.most are gases at room temperature
3)brittle
4)dull
5)low density or heavy
6)form negative ions when react
7)react with oxygen to form acidic oxide

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17
Q

Carbon derivative

A

Graphite-good conductor
Diamond-very hard and ver high melting point

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18
Q

What is compound?

A

A substance made by two or more elements with fixed proportions .It has different properties from its elements

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19
Q

What is atomic number(Z)?

A

The number of protons in the nucleus

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20
Q

What is mass number(A)?

A

The number of protons + number of neutrons

also known as nucleon number

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21
Q

What is isotopes?

A

Atoms with the same atomic number but different mass number

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22
Q

What are ions

A

when atom loses or gains an electron it becomes ions

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23
Q

How positive ions form?

A

When atom loses electrons it forms a positive ions or cations

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24
Q

How anions can be formed?

A

When atom gains electrons it forms a negative ions or anions

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25
Q

instrument that used to measure the mass of an atom

A

Mass spectrometer

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26
Q

Electromagnetic spectrum

A

Low energy radio waves to high energy gamma waves

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27
Q

What electromagnetic radiation an atom can emit?

A

Infrared radiation

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28
Q

How absorption spectrum is produced?

A

When electromagnetic radiation pass through a collection of atoms some of the radiation is absorbed and used to excite the atoms from lower energy to higher level energy

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29
Q

What will happen when atom absorb energy?

A

an electron moves from lower energy level (ground state) to higher energy level(excited state).
But the excited state is unstable and the electron fall into ground state and giving off energy in the form of electromagnetic radiation (Photon).
The energy released is proportional to frequency of the radiation

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30
Q

Planck equation explanation

A

The energy of photon is equal to the energy of change in atom
^Eelectron=Ephoton

By Planck eq:Ephoton=hv

^Eelectron=hv

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31
Q

energy level and radiation

A

n=1,ultraviolet
n=2,visible light
n=3>above,infrared radiation

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32
Q

Electron have _____ properties

A

wave

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33
Q

What is an atomic orbital?

A

a region around nucleus in which there is 90% probability of finding the electrons

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34
Q

First energy level

A

contains one 1s orbital
Lowest energy level
Can hold 2e

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35
Q

2nd energy

A

Contains one 2s and three 2p orbitals
can hold 10e

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36
Q

Pauli Exclusion

A

No more than two electrons can occupy any one orbital, and if 2e are in same orbital they must spin in opposite directions

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37
Q

Hund’s rule

A

If more than one orbital in a sub-level is available,electrons occupy different orbitals with parallel spins

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38
Q

How transition metals lose electrons?

A

They lose electrons from 4s sub level before 3d sub level

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39
Q

What is ionization energy?

A

The energy needed to remove one mole of electrons from the ground state of one mole of the gaseous atom

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40
Q

What is the charge if proton and electron?

A

Charge of proton= +1.67*10^-19C

Charge of electron = -1.67*10^-19C

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41
Q

Which particle has the greatest number of mass?

Proton? Neuton? Electron?

A

Neutron has the greatest number of charge.

Although the mass of both neutron and proton are approximately 1amu, neutron has slightly heavier mass.

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42
Q

A
X
Z

Name the symbols?

A

A=Mass number(no of proton +no.of neutron)
X=element
Z=Atomic number(no. of proton)

43
Q

What is approximately equal to the atomic mass of an atom?

A

An atom consists of protons,neutrons and electrons.
Mass of the electrons is negligible therefore the atomic mass of an atom is approximately equal to the mass number(no. of proton+no. of neutron)
But the presence of isotopes=atomic number may not be whole number

44
Q

What is the formula to find average mass(atomic mass of an atom)?

A

Average mass=percent abundance * mass of an isotope

45
Q

How do we find empirical formula?

A

1.Find the moles of the atom
2.Ratio cha
3.Divide by smallest no

46
Q

How do we find molecular number ?

A

Molar mass of molecular formula =x*molar mass of empirical formula

47
Q

How do we find molecular formula?

A

Molar mass of molecular formula =x*molar mass of empirical formula

48
Q

What would an electron do if it moves to different orbit?

A

It would emit or absorb a photin if it moves to different orbit

^E=hv=E1-E2=-k(1/n2^2-1/n1^2)

h=6.626210^-34Js
k=2.178
10^-18J

49
Q

What is hydrogen like atom?

What is the energy expression for hydrogen like atom?

A

Hydrogenလိုမျိုးoutermost shellမှာ one eပဲရှိတဲ့atomတွေကိုhydrogen like atom

E=-kZ^2/n^2

(Z=nuclear charge,+1 for H,+2 for He,+3 for Li)

k=2.178*10^-18J
n=number of shells

50
Q

Which orbital has lowest energy level?

A

The orbital closest to the nucleus has the lowest energy n=1

51
Q

As the orbital becomes far from nucleus,which energy increases and which decreases?

A

The energy of the orbitals and energy of the electron increases and the energy of nuclear attraction decreases

52
Q

How do you find the valence electrons in atoms?

A

By looking at the electronic configuration,electrons in the highest energy shell is the valence electrons

53
Q

What is the electronic configuration of Cr 24?

A

1s2 2s2 2p6 3s2 3p6 4s1 3d5 (d sub shellမှာhalf filled ဖြစ်ချင်လို့ 4sကနေတစ်လုံးယူ)

54
Q

What is the electronic configuration of Cu 29?

A

1s2 2s2 2p6 3s2 3p6 4s1 3d10
(d sub shellမှာfully filledဖြစ်ဖို့4s sub shellကနေone electronယူ)

55
Q

What are the differences between main group elements and transition elements?

A

Main group elements have outermost electrons added to s and p sub-shell.if the electrons are in d sub-shell,they are fully filled(10e in d sub-shells)

56
Q

What is the valence electrons of gallium? Ga=31

A

1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2

(3d=10eမလို့ 4s and 4pမှာvalence electron=3)

57
Q

What is transition elements?

A

Partially filled electrons in d-sub shells

But Cu,Zn,Au,Ag, Hg have fully filled electrons in d sub shell, but they are transition elements group in periodic table

58
Q

Mass of proton and neutron,which is heavier?

A

1amu
Neutron is slightly heavier

59
Q

Atom has many_____

A

empty spaces

60
Q

Function of neutron

A

Hold the positively charged protons in the nucleus

61
Q

How can isotopes of elements exist?

A

The same atomic number but different mass number-different number neutrons

Isotopes——>same chemical properties b/c they have the same atomic number

but different physical properties such as boiling point and melting point,density and gaseous diffusion

62
Q

How do u find average atomic mass of elements which have isotopes?

A

Average atomic mass=total mass/number of atoms

Eg.100 Cl atoms-relative abundance of 35Cl=77.5 atoms and 37Cl=22.5atoms

total mass=77.535+22.537=3545
number of atoms=100

Relative atomic mass=3545/100=35.45

63
Q

When a chemical reaction occurs,what us the number that change?

The number of proton? neutron? electron?

A

Electron

the other two doesn’t change

64
Q

Na atoms are very reactive and gives off heat when dissolved in water but we are eating common salt,why isn’t it dangerous?

A

We eat Na+ ions,which is not reactive

65
Q

Elements with 19protons,20neutrons and 18 electrons

A

By looking protons , potassium cation

66
Q

sub atomic particles of 40Ca^2+

A

number of proton=20
number of neutrons =20
number of electrons =20-2=18

67
Q

Although the mass number of carbon is 12,the relative atomic mass measured by spectrometer is slightly larger,why?

A

b/c of the occurrence of carbon 12,carbon 13 and carbon 14 isotopes

68
Q

How the frequency is proportional to the wavelength ?

A

inversely proportional

V=f lambda

69
Q

Electrons release energy when it____

A

moves from one orbital to another

^E electron= E photon

E photon=hv

^E electron=hv

70
Q

Which electron transition involves the greatest release of energy?
1)n=2 to n=6
2)n=6 to n=4
3)n=1 to n=7
4)n=3 to n=1
5)n=7 to n=2

A

Ans:4

n1=UV
n2=visible light
n3=infrared
n4=infrared
n5=infrared

therefore, energy given out is maximum when the electrons from the higher state falls into the lowest energy sub shell.DO NOT DECIDE BY DIFFERENCE IN NUMBERS

71
Q

Why do the lines converge at higher energies?

A

B/c energy levels inside the atom are closer together at higher energy

eg.3d and 4s energy level are similar ____transition elements have variable oxidation numbers

72
Q

Emission spectrum and absorption light spectrum,which can be used to guess the electronic configuration?

A

When an electron moves to higher energy from the lower energy level——->the spectrometer analyzes the transmitted radiation——->absorption

Emission spectrum-lines not appeared on the absorption spectrum and visible only when high voltage is applied

Emission spectrum____analyze_____information about the electronic configuration of different atoms

73
Q

Each orbital can hold only ______ electrons

A

two

eg.p orbitals——>6e

Px,Py,Pz-2e each

74
Q

How many sub orbitals are there in energy level 1,2,3,4?

A

1-s
2-s+p
3-s+p+d
4-s+p+d+f

75
Q

Shape of s orbital

A

spherical

76
Q

Shape of p orbital

A

dumbbell shape-arranged at 90 degree to each other

77
Q

number of sub orbitals in each orbital

A

s-1
p-3
d-5
f-7

78
Q

the formula of number of electrons in the energy level

A

2n^2 (squared)

79
Q

When adding electrons to the orbitals,electrons are filled first in _____ orbital

A

lower energy

80
Q

electronic configuration of calcium

A

20Ca-1s2 2s2 2p6 3s2 3p6 4s2

81
Q

How many orbitals are located in 3rd energy level?

A

1s+3p+5d=9

82
Q

electronic configuration of Cr3+

A

24 Cr 3+____1s2 2s2 2p6 3s2 3p6 4s2 3d3

83
Q

electronic configuration of S2-

A

16S2-____1s2 2s2 2p6 3s2 3p6

84
Q

Elements whose valence electrons in s sub level make up_____ of periodic table

A

s block

85
Q

Elements whose valence electrons in p sub level make up_____ of periodic table

A

p block

86
Q

Elements whose valence electrons in d sub level make up_____ of periodic table

A

d block

87
Q

Elements whose valence electrons in f sub level make up_____ of periodic table

A

f block

88
Q

once the ionization energy is added to remove an electron from the atom, the electron is taken away from the nucleus and can be considered n=

A

infinity

89
Q

the mass of an atom is determined by ____

A

mass of proton and neutron

90
Q

one element that does not have neutron

A

hydrogen

91
Q

What is the charge of a proton and an electron?

A

Charge of a proton= +1.6710^-19 C Charge of an electon= -1.6710^-19 C

92
Q

Which particle has the greatest number of mass? Proton ? Neutron? Electron?

A

Neutron has the greatest number of charge.
Although the mass of both protons and neutrons are approximately 1 amu, neutrons has a slight heavier mass.

93
Q

A
X
z

Name the symbols in an atomic structure of an element .

A

A=mass number (no of protons+no of neutrons)
X=element
Z= atomic number (no of protons)

94
Q

What is approximately equal to the atomic mass of an atom?

A

An atom consists of protons, neutrons and electrons.
Mass of an electron is too small so negligible, therefore, atomic mass of an atom is approximately equal to the mass number (no of protons+no of neutrons). but presence of isotopes= atomic number may not be whole number

95
Q

What is the formula to find average mass( atomic mass of an atom)

A

Average mass= percent abundance * mass of an isotope

96
Q

How do we find empirical formula?

A

1find the moles of the atom,
2. Ratio cha
3. Divide by the smallest no

97
Q

How do we find molecular formula?

A

Molar mass of molecular formula= x * molar mass of empirical formula

98
Q

What would an electron do if it moves to a different orbit?

A

It would emit or absorb a proton if it moves to a different orbit

99
Q

What is the hydrogen like atom?
What is the energy expression for hydrogen like atom?

A

hydrogen လိုမျိုး Outer Most Shell မှာ one ē ဘဲရှိတဲ့ atoms တွေကို hydrogen like atoms

100
Q

Which orbital has the lowest energy level?

A

The orbital closest to the nucleus has the lowest energy level. n=1

101
Q

As the orbital becomes far from the nucleus, which energy increases and which decreases?

A

The energy of the orbitals and energy of the electrons increases, and the energy of the nuclear attraction decreases.

102
Q

How do you find the valence electrons of atoms?

A

By looking at the electronic configuration, electrons in the highest energy shell is the valence electrons

103
Q

What are the difference between main grp elements and transition elements?

A

Main group elements have outermost electron added to s or p subshells. If the electrons are in d sub shell, there are fully filled (10 electrons in d subshells)

104
Q

What is the transition element?

A

Partially filled electrons in d subshells.

But Cu, Zn, Au, Ag, Hg have fully filled electrons in d subshells, but they are in transition elements groups in periodic table.