Atomic structure Flashcards
1
Q
What is atom?
A
Atoms are smallest particles of matter
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
3
Q
Do artificial elements are stable?
A
No,30 artificial are produced in lab and they are very unstable
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
5
Q
What can we know from the rows of periodic table?
A
Periods(i.e.energy shells)
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.
7
Q
How subatomic particles are measured?
A
Atomic mass unit
8
Q
Charge of subatomic particles
A
Proton-positive charge (+1)
Neutron-neutral
Electron-negative charge(-1)
9
Q
What are isotopes?
A
Atoms of the same element with different numbers of neutrons
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.
11
Q
What is electron shell?
A
Electrons are arranged in shells around nucleus.
12
Q
The energy of the 1st shell
A
Since it is the closest to the nucleus and it has lowest energy level
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
14
Q
Why group 0 are unreactive?
A
B/c they have very stable arrangement of electrons (no valence shell)
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
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
17
Q
Carbon derivative
A
Graphite-good conductor
Diamond-very hard and ver high melting point
18
Q
What is compound?
A
A substance made by two or more elements with fixed proportions .It has different properties from its elements
19
Q
What is atomic number(Z)?
A
The number of protons in the nucleus
20
Q
What is mass number(A)?
A
The number of protons + number of neutrons
also known as nucleon number
21
Q
What is isotopes?
A
Atoms with the same atomic number but different mass number
22
Q
What are ions
A
when atom loses or gains an electron it becomes ions
23
Q
How positive ions form?
A
When atom loses electrons it forms a positive ions or cations
24
Q
How anions can be formed?
A
When atom gains electrons it forms a negative ions or anions
25
instrument that used to measure the mass of an atom
Mass spectrometer
26
Electromagnetic spectrum
Low energy radio waves to high energy gamma waves
27
What electromagnetic radiation an atom can emit?
Infrared radiation
28
How absorption spectrum is produced?
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
29
What will happen when atom absorb energy?
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
30
Planck equation explanation
The energy of photon is equal to the energy of change in atom
^Eelectron=Ephoton
By Planck eq:Ephoton=hv
^Eelectron=hv
31
energy level and radiation
n=1,ultraviolet
n=2,visible light
n=3>above,infrared radiation
32
Electron have _____ properties
wave
33
What is an atomic orbital?
a region around nucleus in which there is 90% probability of finding the electrons
34
First energy level
contains one 1s orbital
Lowest energy level
Can hold 2e
35
2nd energy
Contains one 2s and three 2p orbitals
can hold 10e
36
Pauli Exclusion
No more than two electrons can occupy any one orbital, and if 2e are in same orbital they must spin in opposite directions
37
Hund’s rule
If more than one orbital in a sub-level is available,electrons occupy different orbitals with parallel spins
38
How transition metals lose electrons?
They lose electrons from 4s sub level before 3d sub level
39
What is ionization energy?
The energy needed to remove one mole of electrons from the ground state of one mole of the gaseous atom
40
What is the charge if proton and electron?
Charge of proton= +1.67*10^-19C
Charge of electron = -1.67*10^-19C
41
Which particle has the greatest number of mass?
Proton? Neuton? Electron?
Neutron has the greatest number of charge.
Although the mass of both neutron and proton are approximately 1amu, neutron has slightly heavier mass.
42
A
X
Z
Name the symbols?
A=Mass number(no of proton +no.of neutron)
X=element
Z=Atomic number(no. of proton)
43
What is approximately equal to the atomic mass of an atom?
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
What is the formula to find average mass(atomic mass of an atom)?
Average mass=percent abundance * mass of an isotope
45
How do we find empirical formula?
1.Find the moles of the atom
2.Ratio cha
3.Divide by smallest no
46
How do we find molecular number ?
Molar mass of molecular formula =x*molar mass of empirical formula
47
How do we find molecular formula?
Molar mass of molecular formula =x*molar mass of empirical formula
48
What would an electron do if it moves to different orbit?
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=6.6262*10^-34Js
k=2.178*10^-18J
49
What is hydrogen like atom?
What is the energy expression for hydrogen like atom?
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
Which orbital has lowest energy level?
The orbital closest to the nucleus has the lowest energy n=1
51
As the orbital becomes far from nucleus,which energy increases and which decreases?
The energy of the orbitals and energy of the electron increases and the energy of nuclear attraction decreases
52
How do you find the valence electrons in atoms?
By looking at the electronic configuration,electrons in the highest energy shell is the valence electrons
53
What is the electronic configuration of Cr 24?
1s2 2s2 2p6 3s2 3p6 4s1 3d5 (d sub shellမှာhalf filled ဖြစ်ချင်လို့ 4sကနေတစ်လုံးယူ)
54
What is the electronic configuration of Cu 29?
1s2 2s2 2p6 3s2 3p6 4s1 3d10
(d sub shellမှာfully filledဖြစ်ဖို့4s sub shellကနေone electronယူ)
55
What are the differences between main group elements and transition elements?
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
What is the valence electrons of gallium? Ga=31
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2
(3d=10eမလို့ 4s and 4pမှာvalence electron=3)
57
What is transition elements?
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
Mass of proton and neutron,which is heavier?
1amu
Neutron is slightly heavier
59
Atom has many_____
empty spaces
60
Function of neutron
Hold the positively charged protons in the nucleus
61
How can isotopes of elements exist?
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
How do u find average atomic mass of elements which have isotopes?
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=77.5*35+22.5*37=3545
number of atoms=100
Relative atomic mass=3545/100=35.45
63
When a chemical reaction occurs,what us the number that change?
The number of proton? neutron? electron?
Electron
the other two doesn’t change
64
Na atoms are very reactive and gives off heat when dissolved in water but we are eating common salt,why isn’t it dangerous?
We eat Na+ ions,which is not reactive
65
Elements with 19protons,20neutrons and 18 electrons
By looking protons , potassium cation
66
sub atomic particles of 40Ca^2+
number of proton=20
number of neutrons =20
number of electrons =20-2=18
67
Although the mass number of carbon is 12,the relative atomic mass measured by spectrometer is slightly larger,why?
b/c of the occurrence of carbon 12,carbon 13 and carbon 14 isotopes
68
How the frequency is proportional to the wavelength ?
inversely proportional
V=f lambda
69
Electrons release energy when it____
moves from one orbital to another
^E electron= E photon
E photon=hv
^E electron=hv
70
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
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
Why do the lines converge at higher energies?
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
Emission spectrum and absorption light spectrum,which can be used to guess the electronic configuration?
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
Each orbital can hold only ______ electrons
two
eg.p orbitals——>6e
Px,Py,Pz-2e each
74
How many sub orbitals are there in energy level 1,2,3,4?
1-s
2-s+p
3-s+p+d
4-s+p+d+f
75
Shape of s orbital
spherical
76
Shape of p orbital
dumbbell shape-arranged at 90 degree to each other
77
number of sub orbitals in each orbital
s-1
p-3
d-5
f-7
78
the formula of number of electrons in the energy level
2n^2 (squared)
79
When adding electrons to the orbitals,electrons are filled first in _____ orbital
lower energy
80
electronic configuration of calcium
20Ca-1s2 2s2 2p6 3s2 3p6 4s2
81
How many orbitals are located in 3rd energy level?
1s+3p+5d=9
82
electronic configuration of Cr3+
24 Cr 3+____1s2 2s2 2p6 3s2 3p6 4s2 3d3
83
electronic configuration of S2-
16S2-____1s2 2s2 2p6 3s2 3p6
84
Elements whose valence electrons in s sub level make up_____ of periodic table
s block
85
Elements whose valence electrons in p sub level make up_____ of periodic table
p block
86
Elements whose valence electrons in d sub level make up_____ of periodic table
d block
87
Elements whose valence electrons in f sub level make up_____ of periodic table
f block
88
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=
infinity
89
the mass of an atom is determined by ____
mass of proton and neutron
90
one element that does not have neutron
hydrogen
91
What is the charge of a proton and an electron?
Charge of a proton= +1.67*10^-19 C Charge of an electon= -1.67*10^-19 C
92
Which particle has the greatest number of mass? Proton ? Neutron? Electron?
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
A
X
z
Name the symbols in an atomic structure of an element .
A=mass number (no of protons+no of neutrons)
X=element
Z= atomic number (no of protons)
94
What is approximately equal to the atomic mass of an atom?
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
What is the formula to find average mass( atomic mass of an atom)
Average mass= percent abundance * mass of an isotope
96
How do we find empirical formula?
1find the moles of the atom,
2. Ratio cha
3. Divide by the smallest no
97
How do we find molecular formula?
Molar mass of molecular formula= x * molar mass of empirical formula
98
What would an electron do if it moves to a different orbit?
It would emit or absorb a proton if it moves to a different orbit
99
What is the hydrogen like atom?
What is the energy expression for hydrogen like atom?
hydrogen လိုမျိုး Outer Most Shell မှာ one ē ဘဲရှိတဲ့ atoms တွေကို hydrogen like atoms
100
Which orbital has the lowest energy level?
The orbital closest to the nucleus has the lowest energy level. n=1
101
As the orbital becomes far from the nucleus, which energy increases and which decreases?
The energy of the orbitals and energy of the electrons increases, and the energy of the nuclear attraction decreases.
102
How do you find the valence electrons of atoms?
By looking at the electronic configuration, electrons in the highest energy shell is the valence electrons
103
What are the difference between main grp elements and transition elements?
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
What is the transition element?
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.
