Question

which of the following pairs are atoms of the same element?
a 5 protons, 3 neutrons 5 protons, 4 neutrons
b 4 protons, 4 neutrons 3 protons, 4 neutrons
c 3 protons, 4 neutrons 4 protons, 4 neutrons
d 5 protons, 4 neutrons 4 protons, 3 neutrons
how many protons are in an atom represented by $_{90}^{222}th$?

Explanation:

First Question (Which of the following pairs are atoms of the same element?)

To determine if two atoms are of the same element, we check the number of protons (atomic number). Same number of protons means same element.

• Option A: Atom X has 5 protons, Atom Y has 5 protons. Same proton count.
• Option B: Atom X has 4 protons, Atom Y has 3 protons. Different.
• Option C: Atom X has 3 protons, Atom Y has 4 protons. Different.
• Option D: Atom X has 5 protons, Atom Y has 4 protons. Different.

Step1: Recall atomic notation

In the notation $_{Z}^{A}\text{Element}$, $Z$ is the atomic number (number of protons), and $A$ is the mass number (protons + neutrons).

Step2: Identify $Z$ for Th

For $_{90}^{232}\text{Th}$, the subscript $Z = 90$. So the number of protons is 90.

Answer:

A. Atom X: 5 protons, 3 neutrons; Atom Y: 5 protons, 4 neutrons

Second Question (How many protons are in an atom represented by $\boldsymbol{_{90}^{232}Th}$?)