Chemistry Atomic Radius Concepts

Questions and Answers

What accurately defines atomic radius?

The distance from the nucleus to the ionization energy level.

Half the distance between the nuclei of two atoms joined by a single covalent bond. (correct)

The average distance between the nucleus and the outermost electron.

The total distance from the nucleus to the electron cloud.

Which factors contribute to the decrease in atomic radius across a period?

Increased nuclear charge and the same screening effect. (correct)

Decreased screening effect and increased ionization energy.

Increased atomic mass and decreased electron shielding.

Decreased nuclear charge and increased atomic size.

What reasons chiefly explain the increase in atomic radius down a group?

Extra energy levels, increased screening, and offsetting nuclear charge. (correct)

Higher ionization energy and reduced nuclear attraction.

Decreased electronegativity and increased effective nuclear charge.

Increased nuclear size and stronger bonding forces.

Which description most accurately defines 1st ionisation energy?

The minimum energy required to remove the most loosely bound electron from 1 mole of gaseous atoms. Signup and view all the answers

What are the main reasons for the increase in 1st ionisation energy across a period?

Increased nuclear charge and decreased atomic radius. Signup and view all the answers

Which combination leads to a decrease in 1st ionisation energy down a group?

Increased atomic radius and increased screening. Signup and view all the answers

What is the effect of increasing atomic radius on electronegativity trends down a group?

Decreases electronegativity, making it less attractive to electrons. Signup and view all the answers

What is the relationship between 1st ionisation energy and atomic radius across a period?

As atomic radius decreases, 1st ionisation energy increases. Signup and view all the answers

How does increased nuclear charge across a period impact electronegativity?

Increases electronegativity, enhancing attraction to electrons. Signup and view all the answers

Which of the following is the proper definition of electronegativity?

A measure of an atom's ability to attract and hold electrons. Signup and view all the answers

Study Notes

Atomic Radius

Defined as half the distance between the nuclei of two atoms of the same element bonded by a single covalent bond.
Decreases across a period due to increased nuclear charge and minimal effect of the screening effect.
Increases down a group due to extra energy levels, increased screening, and offsetting the increase in nuclear charge.

Electronegativity

Defined as the relative attraction that an element's nucleus has on shared electrons in a covalent bond.
Increases across a period due to higher nuclear charge and smaller atomic radius, making atoms more attractive to electrons.
Decreases down a group because the increased atomic radius decreases attraction to shared electrons.

Ionisation Energy

1st ionisation energy is the minimum energy needed to remove the most loosely bound electron from 1 mole of gaseous atoms in the ground state.
Increases across a period owing to increased nuclear charge and decreased atomic radius.
Decreases down a group due to increased atomic radius and increased screening effect.

Second Ionisation Energy

Defined as the minimum energy required to remove the most loosely bound electron from a singly charged positive ion.

Reactivity

Reactivity increases down a group as outermost electrons are further from the nucleus, making them less tightly held and easier to bond with other atoms.

Ionisation Energy Trends

Large jumps between ionisation energies indicate the presence of distinct energy levels within an atom.
The relationship between 1st ionisation energy and atomic radius within a period shows that as atomic radius decreases, 1st ionisation energy increases.

Influences on Trends

Increased nuclear charge across a period enhances electronegativity by making the nucleus more attractive to electrons, enhancing bonding capabilities.

Description

This quiz covers key concepts about atomic radius, including its definition and factors influencing its change across periods and down groups. Test your understanding of how nuclear charge and screening effects contribute to atomic size variations. Perfect for chemistry students seeking to enhance their knowledge of atomic structure.