protons
All elements in the same group have the same number of valence electrons.
Same elements of group have same valency. They possess same chemical behaviour.
All elements in the same horizontal row of the Periodic Table are in the same period, there are 7 periods.
All elements in a group have same chemical properties. They have same number of valence electrons.
They have the same number of protons
All elements in the groups (excluding transition metals) have the same number of electrons as the group number.
Elements with the same number of valence electrons are found in the same group or column of the periodic table. This is because elements in the same group have the same number of valence electrons, which determines their chemical properties. For example, all elements in group 1 have 1 valence electron.
All elements in the same A group will have the same number of valence electrons.
Outer or valence electrons
no my dear the elements are not of the same type, and they don't have the same atom number refer to the periodic table and you will see
they all have the same electrons.
Elements are not mixture of all. An element entirely of atoms of the same type.