Question

Which of the following factors are especially important in determining whether an element has metallic properties?

• A. Atomic number
• B. Atomic weight
• C. Number of valence electrons
• D. Number of vacant atomic orbitals
• E. Total number of electronic shells in the atom

Answer 1

Answer: (A), (C)

Atomic number
Number of valence electrons

Atomic number and number of valence electrons determines the property of an element, whether it is metal or non metal, atomic weight, number of vacant atomic orbitals and total number of electronic shells in the atom has no effect on the metallic property of an element.
Generally the elements which lies left hand side of the periodic table that is $IA$ and $IIA$ elements are metals which contain 1 and 2 valence electrons respectively.