Question

How do elements change as you move to the right along a row in the periodic table?

The atomic number decreases.

The electronegativity decreases.

The average atomic mass increases.

The number of valence electrons decreases.

Answer 1

The average atomic mass increases.
a) is wrong because as you move across a period the atomic number increases
b) is wrong because across a period the atomic radius decreases therefore the ability of an atom to gain an electron increases.
d) is wrong as moving across a period means an increasing group number and the group number is the number of valence electrons.