Unit 2 Review

What causes the shielding effect to remain constant as additional valence electrons are added across a period?

• The atomic radius increases as valence electrons are added

• The charge on the nucleus is constant across a period

• The valence electrons are added to different energy levels of the period

• The number of core electrons does not change as electrons are added to valence subshells of the period

What charge will this atom have when it ionizes to its most stable ionic form?

• 2-

• 6-

• 0 because it already has a full octet and will not ionize.

• 2+

Which of the following has the same number of valence electrons as the atom in the diagram?

• Neon (Ne)

• Phosphorus (P)

• Iodine (I)

• Selenium (Se)

Which group number does the atom in the diagram belong to?

• 2

• 6

• 16

• 18

The full ground state electron configuration of zinc (Zn) is above. When zinc becomes a cation, it will lose electrons from which subshell?

• 3s

• 3p

• 4s

• 3d

Select the piece of evidence that best supports the statement: When comparing two atoms, the ionization energy decreases when the shielding effect increases.

• Comparison of the ionization energy data points for As and Br

• Comparison of the ionization energy data points for Ar and K

• Comparison of the ionization energy data points for B and C

• Comparison of the ionization energy data points for Li and Na

There is a large increase in ionization energy between the first and last elements of each period. For example, lithium (Li) has 500 kJ/mol of ionization energy as the first element in the second period and neon (Ne) has 2100 kJ/mol as the last element in the period. Which is the best explanation for why this occurs?

• Effective nuclear charge increases as you move from left to right across a period

• Electron shielding increases as you move from left to right across a period

• Electron shielding stays the same as you move from top to bottom down a group

• Effective nuclear charge and electron shielding are not involved in why the ionization energy changes

Neutral atoms of elements with higher electronegativities…

• will tend to lose electrons instead of gaining them during ionization.

• will form positively charged ions.

• have a larger effective nuclear charge.

• experience less attraction between the nucleus and valence electrons within an atom.

Which of the following ions is isoelectronic to argon (Ar)?

• Mg2+

• Be2+

• O2-

• Cl-

Which of the following statements about this graph of successive ionization energies of a single atom is TRUE?

• The atom is in group 12.

• The atom has 3 valence electrons.

• The atom will ionize to form an anion.

• The atom has 11 core electrons.