Question

waveground worksheets
name
electron configuration quiz
class
total questions: 25
date
worksheet time: 14mins

1. which of the following is the correct electron configuration for sodium (na)?

a) 1s²2s²2p⁶3s¹
b) 1s²2s²2p⁶3s²
c) 1s²2s²2p⁶3s⁰
d) 1s²2s²2p⁶3p¹

1. what is the electron configuration for cobalt (co)?

a) ar 4s²3d⁷
b) ar 4s¹3d⁸
c) ar 4s⁰3d⁹
d) ar 4s³3d⁶

1. which of the following elements has the electron configuration kr 5s²4d⁷?

a) silver (ag)
b) antimony (sb)
c) osmium (os)
d) rubidium (rb)

1. why is the electron configuration 1s²2s²2p⁶3s²3p⁶4s²4d¹⁰4p⁶ considered invalid?

a) 4d cannot exist before 4p.
b) 3p comes after 3s.
c) radium is not a noble gas.
d) an element cannot be its own electron configuration.

1. which of the following is the correct electron configuration for radium (ra)?

a) rn 7s²
b) rn 7s¹
c) rn 6s²
d) rn 6s¹

1. which of the following is the correct complete ground state electron configuration for oxygen?

a) 1s² 2s¹ 2p⁵
b) 1s² 2s² 2p⁴
c) 1s² 2s² 2p⁶
d) 1s² 2s¹ 2p⁴

Explanation:

Step1: Solve Q1: Na electron config

Sodium (Na, atomic number 11) fills orbitals in order: $1s^22s^22p^63s^1$

Step2: Solve Q2: Co electron config

Cobalt (Co, atomic number 27) uses argon core: $[Ar]4s^23d^7$

Step3: Solve Q3: Identify $[Kr]5s^24d^{10}$ element

This matches silver (Ag, atomic number 47)

Step4: Solve Q4: Invalid config reason

Orbital filling rule: 4d fills only after 4p is full, so $1s^22s^22p^63s^23p^64s^24d^{10}4p^6$ skips 4p first.

Step5: Solve Q5: Ra electron config

Radium (Ra, atomic number 88) uses radon core: $[Rn]7s^2$

Step6: Solve Q6: O electron config

Oxygen (O, atomic number 8) fills orbitals: $1s^22s^22p^4$

Answer:

1. b) $1s^22s^22p^63s^1$
2. d) $[Ar]4s^23d^7$
3. a) Silver (Ag)
4. a) 4d cannot exist before 4p.
5. b) $[Rn]7s^2$
6. d) $1s^22s^22p^4$