Question

level 3
what is a substance that is made of only one type of atom?
a. element
b. compound
c. mixture
d. solution
level 3
an aluminium isotope has 13 protons, 13 electrons, and 14 neutrons. what is its mass number?

Explanation:

Q2

To solve this, we recall the definitions: An element is a pure substance made of only one type of atom. A compound is made of two or more different atoms bonded, a mixture has multiple substances, and a solution is a type of mixture. So the substance with one type of atom is an element.

Step1: Recall mass number formula

The mass number of an atom is the sum of protons and neutrons. The formula is $ \text{Mass Number} = \text{Number of Protons} + \text{Number of Neutrons} $.

Step2: Substitute values

Given protons = 13 and neutrons = 14, so $ \text{Mass Number} = 13 + 14 = 27 $.

Answer:

A. Element

Q4