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Worksheet: Ionization Energy and Electron Affinity

Q1:

In which of the following sequences are the ionization energies arranged in order of increasing size? Note that I E X 𝑛 ( ) is the 𝑛 th ionization energy of element X.

  • AIE3( A l ) < IE1( A l ) < IE1( T l ) < IE2( N a )
  • BIE1( A l ) < IE1( T l ) < IE2( N a ) < IE3( A l )
  • CIE1( T l ) < IE2( N a ) < IE1( A l ) < IE3( A l )
  • DIE1( T l ) < IE1( A l ) < IE3( A l ) < IE2( N a )
  • EIE2( N a ) < IE3( A l ) < IE1( T l ) < IE1( A l )

Q2:

Which main group element has the lowest second ionization energy?

  • A B e
  • B F r
  • C O
  • D R a
  • E F

Q3:

An electron is removed from a gaseous atom. For which of the five elements S n , S i , S b , O and T e is this process most endothermic?

  • A S i
  • B S n
  • C S b
  • D O
  • E T e

Q4:

Why is the second ionization energy of N a greater than that of M g ?

  • ARemoving an electron from the M g + ion is assisted by a decrease in pairing energy.
  • BRemoving an electron from the M g + ion produces an empty electron shell.
  • CThe electron removed from the M g + ion has a smaller azimuthal quantum number.
  • DThe electron removed from the M g + ion has a larger principal quantum number.
  • ERemoving an electron from the M g + ion produces an ion with a larger radius.

Q5:

Why does M g have a higher first ionization energy than A l ?

  • APair repulsion in the 3p subshell makes it easier to remove an electron from the A l atom.
  • BIt is more difficult to remove an electron from a filled subshell.
  • CThe A l atom has more valence electrons to remove.
  • DThe 3p subshell of the A l atom is shielded by the 3s subshell.
  • EThe atomic radius of A l is larger.

Q6:

Rank the following atoms in order of increasing first ionization energy: F , L i , N , R b .

  • A L i < R b < N < F
  • B R b < L i < F < N
  • C F < N < L i < R b
  • D R b < L i < N < F
  • E N < F < R b < L i

Q7:

Why is the first ionization energy of B e greater than that of L i ?

  • AElectrons in the p subshell of the B e atom are more effectively shielded by core shell electrons.
  • BThe electron removed from the B e atom has a smaller principal quantum number.
  • CRemoval of an electron from the L i atom is assisted by a decrease in pairing energy.
  • DThere is a larger effective nuclear charge acting on the valence electrons of the B e atom.
  • ERemoving an electron from the L i atom produces an empty electron shell.

Q8:

Why is the electron affinity of F less than that of C l ?

  • AThere is a larger effective nuclear charge acting on the valence electrons of the C l atom.
  • BThe C l atom has a larger nuclear charge.
  • CThe C l atom contains filled d orbitals which shield the valence p subshell less effectively.
  • DThe F atom has a higher electron density so repels the added electron more strongly.
  • EThe C l atom has a lower first ionization energy.

Q9:

Why is the first ionization energy of F greater than that of C l ?

  • AElectrons in the p subshell of the F atom are more effectively shielded by core shell electrons.
  • BThere is a larger effective nuclear charge acting on the valence electrons of the F atom.
  • CElectrons in the p subshell of the F atom are more effectively shielded by valence s electrons.
  • DThe electron removed from the F atom has a smaller principal quantum number.
  • EPairing energy is reduced by a greater amount when an electron is removed from the F atom.

Q10:

Which of the following elements has the greatest first electron affinity?

  • A S
  • B I
  • C S e
  • D C l
  • E B r

Q11:

Which of the following elements has the smallest first ionization energy?

  • A S r
  • B N a
  • C P
  • D R b
  • E B r

Q12:

Rank the following atoms in order of increasing first ionization energy: C a , S , S e , G e .

  • A C a < G e < S < S e
  • B G e < C a < S e < S
  • C S < C a < G e < S e
  • D C a < G e < S e < S
  • E S < S e < C a < G e

Q13:

Why is the first electron affinity of O less than that of F ?

  • AThe pairing energy is greater when an electron is added to the O atom.
  • BElectrons in the p subshell of the O atom are more effectively shielded by core shell electrons.
  • CThe O atom has a higher electron density so repels the added electron more strongly.
  • DThere is a smaller effective nuclear charge acting on the valence electrons of the O atom.
  • EAdding an electron to the F atom produces a full electron shell.

Q14:

Which of the following elements has the highest first ionization energy?

  • A C
  • B B
  • C O
  • D N
  • E B e

Q15:

Which of the following elements has the smallest first ionization energy?

  • A S r
  • B N a
  • C P
  • D R b
  • E B r

Q16:

Which of the following elements has the largest first ionization energy?

  • A B a
  • B M g
  • C B
  • D O
  • E T e

Q17:

Why is the first ionization energy of G a slightly greater than that of A l ?

  • AThe average radial distance of valence electrons from the nucleus is smaller in the G a atom.
  • BThe electron removed from the G a atom has a smaller principal quantum number.
  • CPairing energy is reduced by a greater amount when an electron is removed from the A l atom.
  • DThe G a atom contains filled d orbitals that shield the valence p subshell less effectively.
  • EFor every proton in the nucleus, the valence p electrons in the G a atom are shielded by fewer electrons in lower energy subshells.

Q18:

Rank the following atoms in order of increasing first ionization energy: C a , S , S e , G e .

  • A C a < G e < S < S e
  • B G e < C a < S e < S
  • C S < C a < G e < S e
  • D C a < G e < S e < S
  • E S < S e < C a < G e

Q19:

Which of the following elements has the lowest first ionization energy?

  • A P o
  • B O
  • C P b
  • D B a
  • E S r

Q20:

Why does S have a lower first ionization energy than P ?

  • AThe atomic radius of S is larger.
  • BThe S atom has a higher maximum oxidation state.
  • CIt is more difficult to remove an electron from a subshell if doing so results in an unfilled orbital.
  • DElectrons in the full 3p orbital of the S atom experience pair repulsion.
  • EThe 3p electrons of the S atom are more strongly shielded by the 3s subshell.

Q21:

Which of the following elements has the largest first ionization energy?

  • A B a
  • B M g
  • C B
  • D O
  • E T e

Q22:

Rank the following atoms in order of increasing first ionization energy: F , L i , N , R b .

  • A L i < R b < N < F
  • B R b < L i < F < N
  • C F < N < L i < R b
  • D R b < L i < N < F
  • E N < F < R b < L i

Q23:

An electron is added to a gaseous ion with a charge of +1. For which of the five elements G a , B r , I , K and R b is this process most exothermic?

  • A G a
  • B I
  • C K
  • D B r
  • E R b

Q24:

Rank the elements from N to N e in order of decreasing first ionization energy.

  • A F > O > N > N e
  • B N e > F > O > N
  • C N > O > N e > F
  • D N e > F > N > O
  • E O > N > F > N e

Q25:

An electron is added to a gaseous ion with a charge of 1+. For which of the five elements G a , B r , I , K and R b is this process most exothermic?

  • A G a
  • B I
  • C K
  • D B r
  • E R b