Question

Which of the following elements is a Group 1 metal?
A. He
B. F
C. Ca
D. Cs

Answer 1

Helium (He) is a noble gas. Fluorine (F) is a halogen. Calcium (Ca) is an alkaline earth metal and is located in group 2. Cs is on the furthest left side, hence making it be displayed as an alkaline metal and located in group 1. 

Answer 2

the correct answer is Cesium "Cs"

Step-by-step explanation:

Group 1 metals means alkali metals.

The electronic configuration of alkali metals is such that they have only one valence electron in the outer most shell.

The following are the elements of first group

a) Lithium

b) sodium

c) Potassium

d) Rubidium

e) Cesium

so the correct answer is Cesium "Cs"

A) He : This is noble gas

B) F : This is halogen

C) Ca : This is alkaline earth metal.