Question

the elements of which of the following families are all found as gases and are almost completely unreactive in nature?
○ alkali metals
○ halogens
○ noble gases
○ alkaline earth metals
clear my selection
2 multiple choice 1 point
what is the energy needed to take away a second electron from an ion called?
○ electron affinity
○ second ionization energy
○ ion
○ first ionization energy
clear my selection

Explanation:

First Question (Elements as gases and unreactive)

• Alkali metals: Reactive metals, not gases (except maybe at high temp, but not naturally gaseous).
• Halogens: Reactive non - metals, not all gaseous (e.g., iodine is solid).
• Noble gases: All gaseous at STP, have full valence shells, so almost unreactive.
• Alkaline earth metals: Reactive metals, solid at STP.

• Electron affinity: Energy change when gaining an electron.
• Second ionization energy: Energy to remove a second electron from an ion (after first electron removal).
• Ion: A charged particle, not an energy term.
• First ionization energy: Energy to remove first electron from an atom.

Answer:

C. noble gases

Second Question (Energy to remove second electron)