Question

Consider the following elements

4Be, 9F, 19K, 20Ca

a) Select the element having one election in the outer most shell.

b) Select two elements of the same group.

c) Write the formula and state the nature of the Compound formed when the

element K reacts with an element X of electronic configuration 2, 8, 7.

Answer 1

a) K- Potassium is the element having only one electron in the outermost shell.
b) Beryllium and Calcium lie in the same group as both have a valency of 2.
c) The formula of the reaction of K with X will be KX.
    The nature of the compound formed will be ionic bond. 

Answer 2

A) potassium
B) berilium and calcium
C) It will form kcl (potassium chloride)
It is very corrosive in nature