Worksheet: Electron Configurations of Main Group Elements

In this worksheet, we will practice using the periodic table to deduce the electron configurations of main group (s- and p-block) elements.

Q1:

Which of the following is not a possible electronic configuration of the P atom?

  • A1s2 2s2 2p6 3s1 3p4 3d0
  • B1s2 2s2 2p6 3s2 3p3 3d0
  • C1s2 2s2 2p6 3s1 3p3 3d1
  • D1s2 2s2 2p6 3s2 3p2 3d2
  • E1s2 2s2 2p6 3s0 3p4 3d1

Q2:

Which atom has the electron configuration [ K r ] 4d10 5s2 5p6 in its ground state?

  • A T e
  • B R n
  • C H g
  • D X e
  • E P o

Q3:

Which of the following orbital diagrams describes the electron configuration of the valence shell in the ground-state N a atom?

  • A
    3 p 3 s
  • B
    3 p 3 s
  • C
    3 p 3 s
  • D
    3 p 3 s
  • E
    3 p 3 s

Q4:

Which of the following orbital diagrams describes the electron configuration of the valence shell in the ground-state phosphide ion?

  • A
    3 p 3 s
  • B
    3 p 3 s
  • C
    3 p 3 s
  • D
    3 p 3 s
  • E
    3 p 3 s

Q5:

Which of the following orbital diagrams describes the electron configuration of the valence shell in the ground-state A l 2 + ion?

  • A
    3 p 3 s
  • B
    3 p 3 s
  • C
    3 p 3 s
  • D
    3 p 3 s
  • E
    3 p 3 s

Q6:

What is the electronic configuration of the N a + ion?

  • A1s2 2s2 2p6 3s2
  • B1s2 2s2 2p6 3s1
  • C1s2 2s2 2p6 3s2 3p6
  • D1s2 2s2 2p6
  • E1s2 2s2 2p6 3s2 3p6 4s1

Q7:

What is the electronic configuration of the S n 2 + ion?

  • A1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p2
  • B1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p4
  • C1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s1 5p1
  • D1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2
  • E1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s1 5p2

Q8:

Which of the following has the electronic configuration 1s2 2s2 2p6 3s2 3p5?

  • A F
  • B S 2
  • C F
  • D C l
  • E K +

Q9:

What is the electronic configuration of the N atom?

  • A1s2 2s1 2p4
  • B1s2 2s2 2p4
  • C1s2 2s1 2p3
  • D1s2 2s2 2p3
  • E1s2 2s2 2p6

Q10:

What is the electronic configuration of the S i atom?

  • A1s2 2s2 2p6 3s1 3p3
  • B1s2 2s2 2p6 3s2 3p4
  • C1s2 2s2 2p6 3s2 3p6
  • D1s2 2s2 2p6 3s2 3p2
  • E1s2 2s2 2p6 3s2 3p3

Q11:

What is the electronic configuration of the T e atom?

  • A1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6
  • B1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p2
  • C1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p2 4f2
  • D1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p4
  • E1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 4f4

Q12:

An ion has the electron configuration 1s2 2s2 2p6 3s2 3p6. Which of the following pieces of information would not allow this ion to be precisely identified?

  • ACharge
  • BAtomic number
  • CIonization energy
  • DAtomic mass
  • EIonic radius

Q13:

Which atom has the electron configuration 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d2 5s2?

  • A I n
  • B S r
  • C S n
  • D Z r
  • E Y

Q14:

Which of the following has exactly two unpaired electrons?

  • A C l
  • B P
  • C A l
  • D S i
  • E M g

Q15:

Which atom would be expected to have a half-filled 5p subshell?

  • A B i
  • B A s
  • C G e
  • D S b
  • E S n

Q16:

Which atom would be expected to have a half-filled 4s subshell?

  • A S c
  • B C a
  • C Z n
  • D K
  • E G e

Q17:

Which atom or ion is isoelectronic with B r + ?

  • A K r
  • B S e
  • C G a 3 +
  • D A s
  • E S e 2 +

Q18:

Which atom or ion is isoelectronic with P 2 + ?

  • A S i
  • B M g +
  • C S +
  • D A l
  • E M g

Q19:

What is the name and chemical symbol for the most stable ion of magnesium?

  • AMagnesium ion, M g 2
  • BMagnesite ion, M g 2
  • CMagnesite ion, M g +
  • DMagnesium ion, M g 2 +
  • EMagnesium ion, M g +

Q20:

What is the name and chemical symbol for the most stable ion of nitrogen?

  • ANitride ion, N 3 +
  • BNitrogen ion, N 3
  • CNitrogen ion, N
  • DNitride ion, N 3
  • ENitrogen ion, N 3 +

Q21:

What is the name and chemical symbol for the most stable ion of aluminium?

  • AAluminium ion, A l +
  • BAluminate ion, A l
  • CAluminium ion, A l
  • DAluminium ion, A l 3 +
  • EAluminate ion, A l 3 +

Q22:

What is the name and chemical symbol for the most stable ion of carbon?

  • ACarbon ion, C 4 +
  • BCarbide ion, C 4 +
  • CCarbide ion, C 2
  • DCarbide ion, C 4
  • ECarbon ion, C 2 +

Q23:

An ionic compound entirely consists of aluminium and oxygen. What is the likely empirical formula of this compound?

  • A A l O 3
  • B A l O
  • C A l O 3 2
  • D A l O 2 3
  • E A l O 2

Q24:

An ionic compound entirely consists of sodium and sulfur. What is the likely empirical formula of this compound?

  • A N a S 2
  • B N a S
  • C N a S 3
  • D N a S 2
  • E N a S 3 2

Q25:

Which of the following has exactly two unpaired electrons?

  • A C l
  • B P
  • C A l
  • D S i
  • E M g

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