Q. 4.75 - An Introduction to General, Organic, and Biological Chemistry

Question

a. What is the group number and name of the group that contains potassium?

b. Is potassium a metal, a nonmetal, or a metalloid?

c. How many protons are in an atom of potassium?

d. Potassium has three naturally occurring isotopes. They are $K-39$, $K-40$, and $K-41$. Using the atomic mass of potassium, determine which isotope of potassium is the most abundant.

Step-by-Step Solution

Answer

(a) The group no. is $1$ and group name is hydrogen and alkali metals.

(b) Potassium is a metal

(c) No. of protons are $19$

(d) The most abundant atom is $K-39$

Part (a) Step 1: Given information

We need to find the group no. and group name in which potassium lie.

Part (a) Step 2: Explanation

We know that,

No. of valence electrons in potassium are $1$

Therefore, potassium lies in group no. $1$ named hydrogen and alkali metals.

Part (b) Step 1: Given information

We need to find that potassium is a metal, a nonmetal, or a metalloid 

Part (b) Step 2: Explanation

From part (a) 

It is clear that potassium is a metal

Part (c) Step 1: Given information

We need to find no. of protons in potassium atom

Part (c) Step 2: Explanation

We know that,

Atomic no. of potassium is $19$

And atomic no. is equal to no. of protons.

Therefore, no. of protons are $19$

Part (d) Step 1: Given information

We need to find the most abundant isotope of potassium.

Part (d) Step 2: Explanation

We know that,

In the periodic table, The atomic mass of potassium is $39.09 amu$ which is closest to $39$

Therefore, the most abundant isotope is $K-39$