Question

Which of these elements is a metal? A. hafnium (Hf) B. radon (Rn) C. silicon (Si) D. sulfur (S) E. selenium (Se)

Answer 1

The answer is A. Hafnium

Answer 2

Answer: Option (A) is the correct answer.

Step-by-step explanation:

Substances or elements which lose electrons are known as metals whereas elements which gain electrons are known as non-metals.

For example, electronic configuration of hafnium is
`[Xe]4f^(14)5d^(2)6s^(2)`. It is a transition metal as it has incompletely filled d-orbital so, it will lose electrons to attain stability.

Electronic configuration of radon is
`[Xe]4f^(14)5d^(10)6s^(2)6p^(6)`. Since it is a noble gas it has completely filled orbitals so, it will neither lose nor gain electrons.

Electronic configuration of silicon is
`[Ne]3s^(2)3p^(2)` and it is a non-metal. So, it will gain electrons to complete its octet.

Electronic configuration of sulfur is
`[Ne]3s^(2)3p^(4)` and it is a non-metal. So, it will gain electrons to complete its octet.

Electronic configuration of selenium is
`[Ne]3d^(10)4s^(2)4p^(4)` and it is a non-metals. So, it will gain electrons to complete its octet.

Hence, we can conclude that out of the given options hafnium (Hf) is the element which is a metal.