Which of the following elements is a group 1 metal?
a. he
b. f
c. ca
d. cs

the correct answer is Cesium "Cs"

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.

answer is: naturally occurring solid, inorganic compound or element is mineral.

minerals usually have crystalline form, that means than crystal constituents (atoms, molecules or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.

for example magnetite is a mineral of iron oxide (fe₂o₃).

calcite is a carbonate mineral and the most stable polymorph of calcium carbonate (caco₃).

dolomite is an   carbonate mineral composed of calcium magnesium carbonate (camg(co₃)₂).