They all have the same number of valence electrons in their outer shell
Of what group??
On the Periodic Table of elements, elements that align horizontally are said to be in the same row, and objects that align vertically are said to be in the same group.
Group 1 elements have an oxidation number of +1.
All elements in a group have same chemical properties. They have same number of valence electrons.
Well, some website said that it was in group Va, but what is group Va?
All elements in the groups (excluding transition metals) have the same number of electrons as the group number.
All elements in the same A group will have the same number of valence electrons.
Atomic mass
elements in a group have the same number of valence electrons
Same elements of group have same valency. They possess same chemical behaviour.
All you have to do is look on your periodic table of elements. Metals are to the left and non-metals are to the right. This way we know group four are metals.
All elements in group 16 share similar properties because their valence shells all contain the s2p4 electron configuration.