Question

from which of the following atoms would it be the most difficult to remove an electron?
sodium na
aluminum al
chlorine cl
sulfur s

which group of elements have varying charges?
halogens
transition metals
noble gases
alkali metals

Explanation:

1.

Ionization energy increases across a period from left to right. Chlorine (Cl) is further to the right in the third period compared to Na, Al, and S. Higher ionization energy means it is more difficult to remove an electron.

Transition metals have varying charges because they can lose different numbers of electrons from their \(d\)-orbitals. Halogens usually have a - 1 charge, noble gases are mostly inert (charge of 0), and alkali metals have a + 1 charge.

Answer:

Chlorine Cl

2.