Chemistry Chapter 5: The Periodic Law

Questions and Answers

In the modern periodic table, how are elements ordered?

according to increasing atomic number

What similarity in chemical properties did Mendeleev notice?

certain similarities appeared at regular intervals when arranged by atomic mass

What does the modern periodic law state?

the physical and chemical properties of an element are functions of its atomic number

How did the discovery of noble gases change Mendeleev's periodic table?

by adding a new group Signup and view all the answers

What is the most distinctive property of the noble gases?

largely unreactive Signup and view all the answers

What is the most reactive group in the periodic table?

the alkali metals Signup and view all the answers

What is the atomic number of the second element in group 1?

11 Signup and view all the answers

What is a group in the periodic table?

vertical columns (↑↓) Signup and view all the answers

What is a period in the periodic table?

horizontal rows (↔) Signup and view all the answers

Explain the distinction between atomic mass and atomic number.

atomic # = number of protons; atomic mass = p+n Signup and view all the answers

Give the group numbers for each of the following blocks: s block, p block, d block.

s block: 1-2; p block: 13-18; d block: 3-12 Signup and view all the answers

What happens to energy when an electron is added to a neutral atom?

either absorbed or released Signup and view all the answers

What is the term for the energy required to remove an electron from an atom?

ionization energy Signup and view all the answers

Do electron affinity values generally increase or decrease?

increase (→↑) Signup and view all the answers

Do ionization energy values generally increase or decrease?

increase (→↑) Signup and view all the answers

Do atomic radii tend to become larger or smaller?

smaller (↓←) Signup and view all the answers

Name the halogen with the least electron affinity.

At Signup and view all the answers

Which alkali metal has the highest ionization energy?

Li Signup and view all the answers

Name the element in period 3 with the smallest atomic radius.

Ar Signup and view all the answers

Which group 14 element has the largest electronegativity?

C Signup and view all the answers

Compare the radius of a positive ion to the radius of its neutral atom.

positive is smaller than neutral Signup and view all the answers

Compare the radius of a negative ion to the radius of its neutral atom.

neutral is smaller than negative Signup and view all the answers

Study Notes

Periodic Table Fundamentals

Modern periodic table organizes elements by increasing atomic number.
Mendeleev's original arrangement utilized atomic mass, revealing periodic similarities in chemical properties.

Modern Periodic Law

States that physical and chemical properties depend on an element's atomic number.
The introduction of noble gases created a new group in the periodic table.

Noble Gases and Reactivity

Noble gases are characterized by their largely unreactive nature.
The most reactive group in the periodic table is the alkali metals.

Atomic Structure

Lithium (Li), in group 1, has an atomic number of 3; the second element, sodium (Na), has an atomic number of 11.
Atomic number is defined by the number of protons, while atomic mass includes both protons and neutrons.

Periods and Groups

The periodic table consists of vertical columns (groups) and horizontal rows (periods).
Group numbers for blocks:
- s block: Groups 1-2
- p block: Groups 13-18
- d block: Groups 3-12

Electron Behavior and Energies

Adding an electron to a neutral atom can absorb or release energy.
The energy needed to remove an electron is the atom's ionization energy.

Trends in Elements

Electron affinity values tend to increase across a period.
Ionization energy values also tend to increase from left to right.
Atomic radii generally become smaller as you move across a period.

Specific Element Properties

The halogen with the least electron affinity is Astatine (At).
Lithium (Li) has the highest ionization energy among alkali metals.
The element in period 3 with the smallest atomic radius is Argon (Ar).
Carbon (C) has the largest electronegativity in group 14.

Ion Types and Their Sizes

A positive ion (e.g., Na⁺) is smaller than its neutral counterpart (Na).
A negative ion (e.g., O²⁻) is larger than its neutral atom.

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Description

Test your knowledge on the Periodic Law in Chemistry with this review of Chapter 5. This quiz covers key concepts, such as the arrangement of elements by atomic number and the observations of Mendeleev. Perfect for reinforcing your understanding of the periodic table's structure.