Question

which element is the most reactive nonmetal, most electronegative, and has the highest ionization energy?
gold
helium
fluorine
calcium
15
multiple choice 1 point
which periodic family has a full outermost valence shell and rarely reacts with other elements?
halogens
alkali metals
alkaline earth metals
noble gases

Explanation:

• First question:
• Gold ($Au$) is a metal, so it cannot be the most reactive non - metal.
• Helium ($He$) is a noble gas with a full valence shell. It is very unreactive.
• Calcium ($Ca$) is a metal.
• Fluorine ($F$) is a non - metal. It has a high electronegativity (on the Pauling scale, $F = 3.98$). It is very reactive (it reacts with almost all other elements) and has a high ionization energy (due to its small atomic radius and high nuclear charge for its size).
• Second question:
• Halogens (Group 17) have 7 valence electrons. They are reactive as they tend to gain one electron to complete their octet.
• Alkali metals (Group 1) have 1 valence electron. They are very reactive as they tend to lose that one electron.
• Alkaline earth metals (Group 2) have 2 valence electrons. They are reactive as they tend to lose these two electrons.
• Noble gases (Group 18) have a full outermost valence shell (2 for $He$, 8 for others). They have a very stable electron configuration and rarely react with other elements.

Answer:

• First question: C. Fluorine
• Second question: D. Noble gases