How do elements change from left to right in the periodic tabale?
First, all of the elements to the left of the staircase created by B, SI Ge, As, Sb, Te (metalloids), are all metals. Those to the right are non-metals.
Next the atomic number and therefore the proton number increase as you move from left to right B - 5, C - 6, N -7.
Also the Atomic Mass increases from left to right B - 10.81, C - 12.01,
N - 14.01. There are some exceptions Sg & Bh, Th & Pa, U & Np and Pu & Am.
The Electronegativity also increases as you move from left to right on the periodic table.
Ionization Energy increases from left to right on the periodic table.
Atomic radius decreases moving left to right on the periodic table.
I hope this was helpful.