Electronic Configuration

Question 1

what is an atom?

Answer 1

an atom is the smallest possible unit of an element that retains the properties of that element.

Question 2

the nucleus centre of an atom contains?

Answer 2

neutrons(neutral) and protons(positive)

Question 3

mass number calculation

Answer 3

proton + neutron = mass number

Question 4

Why do all the atoms of a given element have the same number of protons, yet may have different masses?

Answer 4

Given that an element is solely characterized by Z, atoms of same element can have varying N. Such subspecies of elements with same Z but different N and A are termed Isotopes.

Question 5

The four quantum numbers are?

Answer 5

principal, azimuthal, magnetic and spin

Question 6

The principal quantum number is denoted by the letter?

Answer 6

‘n’

Question 7

n represents atomic shell

Answer 7

1, 2, 3, 4

Question 8

The principal energy level is labelled 1-7 from k to q

Answer 8

K=1 L=2 M=3 N=4 O=5 P=6 Q=7

Question 9

How to calculate maximum number of electrons that can occupy an energy level (n)

Answer 9

2n^2

Question 10

azimuthal quantum number is denoted by

Answer 10

‘I’

Question 11

How to calculate number of azimuthal values (I)

Answer 11

I = 0 to I = (n-1)

Question 12

what will be the possible values of I for N-shell?

Answer 12

N shell = 4
I = 0 to I = (n - 1)
I = 0 to I = (4-1)
I = 0, 1, 2, 3.

Question 13

the four sub-levels

Answer 13

s,p,d,f

Question 14

in I quantum number
For l = 0 = S orbital
l = 1 = P orbital
l = 2 = d orbital
l = 3 = f orbital
what if n= 4 and I= 2

Answer 14

4d electron

Question 15

An electron with n= 2 and l = 0 would be?

Answer 15

2s electron

Question 16

magnetic quantum number is denoted by

Answer 16

‘m’

Question 17

the maximum number of orbital spatial orientations (m) is calculated by:

Answer 17

(2l+1) m = l, (l-1), (l-2),…0, -1,-2,… -l. They basically have integer values of -l to 0 to l

Question 18

For S orbital, remember that the value of l = 0, this implies that ml= 0. This interprets that S orbital is oval/spherical in shape hence it has no directional orientation in space.
so what is the m values of D orbital

Answer 18

-2, -1, 0, 1, 2

Question 19

list three functions of quantum numbers

Answer 19

1. They are used to determine the electronic configuration of atoms
2. They are used to determine the location of an atoms electrons.
3. They help us to understand other characteristics of atoms such as ionisation and atomic radius.

Question 20

So why does the spin quantum number have values of either +1/2 or -1/2?

Answer 20

Remember that an electron spins around an axis & has both angular momentum and orbital angular momentum.
So because angular momentum is a vector quantity, the spin quantum number(s) has both magnitude (1/2) and direction (+ or -). Electron can spin only in 2 directions: clockwise and anticlockwise.

Question 21

What are the values of electron spin

Answer 21

+1/2 or -1/2

Question 22

For example, hydrogen has 1 electron in its K shell, so the electron assumes n = 1; hence l = 0 and m = 0; also, s = +1/2.

Answer 22

But for helium with 2 electrons in its “s” orbital, the first electron assumes the same quantum numbers as that of hydrogen i.e. n = 1; hence l = 0 and m = 0; also, s = +1/2. Whereas the 2nd electron assumes a different set of quantum numbers i.e. n = 1; hence l = 0 and m = 0; also, s = -1/2.

Question 23

p orbital arrangment

Answer 23

2px 2py 2pz

Question 24

Are the following two states allowed for N by the Pauli principle?
1s2 2s2 2px1 2py1 2pz1 or 1s2 2s2 2px2 2py1 2pz0

Which is more stable and why?

Answer 24

1s2 2s2 2px()2py()2pz() is more stable than
1s22s22px()2py()2pz()

Half-filled P orbital

Question 25

Maximum number of electrons in a sub shell

Answer 25

2(2l + 1)
“l” being azimuthal number or s,p,d,f. s= 0, p = 1, d= 2, f= 3.

Question 26

The total number of possible orbitals with the same value of l formula

Answer 26

2l + 1