CART - Chemistry Acceleration Readiness Atomic Structure and Periodicity Questions and Answers

Question 1

Which of the following sets of quantum numbers (n, l, m_l, m_s) is invalid for an electron in an atom?

Accepted Answer

4, 3, -4, +1/2

Answer

3, 2, -1, +1/2

Answer

2, 0, 0, -1/2

Answer

1, 0, 0, +1/2

Question 2

An atom has an atomic number of 15 and a mass number of 31. How many protons, neutrons, and electrons does a neutral atom of this element have?

Accepted Answer

15 protons, 16 neutrons, 15 electrons

Answer

15 protons, 15 neutrons, 16 electrons

Answer

16 protons, 15 neutrons, 16 electrons

Answer

31 protons, 15 neutrons, 31 electrons

Question 3

Consider the elements Fluorine (F), Carbon (C), and Oxygen (O). Which of the following correctly lists these elements in order of increasing atomic radius?

Accepted Answer

F, O, C

Answer

C, O, F

Answer

F, C, O

Answer

O, F, C

Question 4

What is the ground-state electron configuration for a sulfide ion (S²⁻)?

Accepted Answer

1s²2s²2p⁶3s²3p⁶

Answer

1s²2s²2p⁶3s²3p⁴

Answer

1s²2s²2p⁶3s²3p²

Answer

1s²2s²2p⁶3s²

Question 5

Which of the following statements best describes the trend of first ionization energy on the periodic table?

Accepted Answer

It decreases down a group and increases from left to right across a period.

Answer

It increases down a group and decreases from left to right across a period.

Answer

It decreases down a group and decreases from left to right across a period.

Answer

It increases down a group and increases from left to right across a period.

Question 6

An unknown element has two naturally occurring isotopes. The first isotope has a mass of 10.0129 amu and an abundance of 19.9%. The second isotope has a mass of 11.0093 amu and an abundance of 80.1%. What is the average atomic mass of this element?

Accepted Answer

10.81 amu

Answer

10.51 amu

Answer

10.01 amu

Answer

11.01 amu