KUMBE | Chapter 2.0 | Atomic Structure | The Answers

CHEMISTRY SK015
2021/2022

SUGGESTED ANSWERS KUMBE TOPIC 2: ATOMIC STRUCTURE

KUMBE 2.1
1.

energy

(d) n=5
n=4
(c) n=3
(b)
n=2

(a) n=1

2. (a)
• When energy is absorbed, the electron at the ground state will absorb the energy and
excited to higher energy level.
• This excited electron is unstable. So it will fall back to lower energy level (n=3) and
released certain amount of energy with certain wavelength and frequency.

(b) ni = 6, nf = 3

1 = ( 1 12 − 1 ) , 1 < 2
22

= 1.097 × 107 −1 (312 − 612)

λ = 1094 nm

(c) energy increase from left to right

(d) The difference in the energy levels of orbital becomes smaller at higher energy levels.

3. (a) Balmer series. CHEMISTRY SK015
(b) 2021/2022
energy
SUGGESTED ANSWERS KUMBE TOPIC 2: ATOMIC STRUCTURE

n=6
n=5
n=4
n=3

n=2

n=1

red cyan blue violet

(c) ni = 5, nf = 2

∆ = ( 1 2 − 1 )
2

= 2.18 × 10−18 (512 − 212)

= -4.58 x 10-19 J

4. (a) n=3

(b) E= −
2

= - (2.18 x 10-18 J)

72

= -4.45 x 10-20 J

5. (a) Balmer series.

(b) 1 = ( 1 12 − 1 ) , 1 < 2
22

486.3 1 m = 1.097 × 107 −1 (212 − 1 )
x 10−9 22

n2 = 4

∴ n=4 to n=2

CHEMISTRY SK015
2021/2022

SUGGESTED ANSWERS KUMBE TOPIC 2: ATOMIC STRUCTURE

6. ∆ = ( − )

= . × − ( − )


= -4.088 x 10-19 J

∆E = hѵ

4.088 x 10-19 J = (6.63 x 10-34 Js-1) ѵ

ѵ = 6.17 x 1014 s-1

KUMBE 2.2 & 2.3

1. (a) n=2, l=1, m=+1, s= +½

permissible

(b) n=1, l=0, m= -1, s= -½

Not permissible

If l=0, m should be 0 only.

(c) n=3, l=3, m= -1, s= +½

Not permissible

If n=3, l should be 0, 1 and 2 only.

(d) not permissible

If n=1 l=0 m only 0

2. (a) A: 1s22s22p63s23p3

B: 1s22s22p63s23p64s23d3

(b) A: 3

B: 3

(c)

zz z z

x yx yx yx y
3s
3px 3py 3pz

CHEMISTRY SK015
2021/2022

SUGGESTED ANSWERS KUMBE TOPIC 2: ATOMIC STRUCTURE

3. a)

1s 2s 2p 3s 3p z z
(b) 2-

X2-: 1s22s22p63s23p6
4. a) Angular Momentum Quantum Number, l.

(b) 3d orbital and 4s orbital

zz

x yx yx yx y
4s 3dxy
22 3dxz

3dx -y

ii. 1s22s22p63s23p64s23d3

iii. J5+: 1s22s22p63s23p6

“Practice isn’t the thing you do once your good. It’s the thing you do that makes you good.” – Malcolm Gladwell