Atomic Structure Practice Quiz

Problem 1

An atom of atomic number 53 and mass number 127 contains how many:

• a. protons?
• b. neutrons?
• c. electrons (if neutral)?

Problem 2

For the atom \({}^{139}_{56}\text{Ba}\), determine:

• a. the number of protons
• b. the number of neutrons
• c. the number of electrons (if neutral)

Problem 3

The number of neutrons in \({}^{108}_{47}\text{Ag}\) is:

Problem 4

The number of protons in \({}^{65}_{30}\text{Zn}\) is:

Problem 5

The number of electrons in a neutral atom of \({}^{27}_{13}\text{Al}\) is:

Problem 6

Draw the isotope notation (nuclear symbol) for an atom with:

• a. 24 protons, 31 neutrons, 24 electrons
• b. 75 protons, 98 neutrons, 75 electrons

Problem 7

Which pair of symbols represents isotopes?

• a. \({}^{23}_{10}\text{Na}\) and \({}^{23}_{11}\text{Na}\)
• b. \({}^{7}_{3}\text{Li}\) and \({}^{8}_{3}\text{Li}\)
• c. \({}^{63}_{29}\text{Cu}\) and \({}^{29}_{63}\text{Cu}\)
• d. \({}^{12}_{23}\text{Mg}\) and \({}^{12}_{24}\text{Mg}\)

Problem 8

Each atom of a specific element has the same:

• a. number of protons
• b. atomic mass
• c. number of neutrons
• d. number of electrons

Problem 9

Substance X has 13 protons, 14 neutrons, and 10 electrons. Determine:

• a. the element's identity
• b. the mass number
• c. the ion charge
• d. whether it's a cation or anion
• e. the complete isotope notation with charge

Problem 10

How many electrons are in each ion?

• a. \(\text{Mg}^{2+}\)
• b. \(\text{S}^{2-}\)
• c. \(\text{Fe}^{3+}\)
• d. \(\text{Br}^{-}\)

Problem 11

Write the isotope notation (including charge) for a particle with:

• a. 18 protons, 23 neutrons, 24 electrons
• b. 53 protons, 70 neutrons, 49 electrons

Problem 12

Fill in all missing values in the table:

Problem 13

Two naturally occurring isotopes of an element have masses and abundances as follows:

• 54.00 amu (20.00%)
• 56.00 amu (80.00%)

What is the average atomic mass of the element?

Problem 14

Calculate the average atomic mass for the element with the following isotopes:

• Element X-23 (63.4%)
• Element X-25 (15.2%)
• Element X-26 (21.4%)

Problem 15

Calculate the average atomic mass for "Dwaxium" with the following isotopes:

• Dwaxium-112 (95.2%)
• Dwaxium-116 (3.1%)
• Dwaxium-118 (1.1%)
• Dwaxium-119 (0.5%)
• Dwaxium-120 (0.1%)

Problem 16

An unknown element has two stable isotopes. The first isotope has a mass of 120.90 amu with an abundance of 57.4%. The second isotope has a mass of 122.90 amu. Calculate the average atomic mass of this element.

Problem 17

A neutral atom has a mass number of 80 and contains 45 neutrons. What is the element, and how many electrons does it have?

Problem 18

An ion has 18 electrons and a charge of 3-. How many protons does this ion have, and what element is it?

Problem 19

Which element is NOT a noble gas?

• a. Ra
• b. Xe
• c. He
• d. Ar

Problem 20

Draw the complete isotope notation (with charge if applicable) for a particle with the following characteristics, then identify if it's an anion, cation, or neutral:

• a. 35 protons, 45 neutrons, 36 electrons
• b. 26 protons, 30 neutrons, 23 electrons
• c. 92 protons, 146 neutrons, 92 electrons