Atomic Structure, the Periodic Table and Bonding

Atoms, the table and bonds

Everything is made of atoms. An atom has a tiny central nucleus of protons, which are positive, and neutrons, which have no charge, surrounded by negative electrons arranged in shells. The atomic number is the number of protons, and the mass number is the protons plus the neutrons, so the number of neutrons is the mass number minus the atomic number. The periodic table arranges all the elements by atomic number, in columns called groups and rows called periods, with metals on the left and non-metals on the right. Atoms join by bonding. Ionic bonding transfers electrons from a metal to a non-metal, covalent bonding shares electrons between non-metals, and metallic bonding holds metal ions in a sea of electrons. This module covers atoms, the table and bonding.

Structure words

Learn these before you match any particle, and remember the atomic number counts the protons.

Ionic against covalent bonding

The two most common bonds form between different kinds of element and in different ways.

How to tell which bond forms

Look at what kinds of element are joining. If a metal meets a non-metal, electrons move across from one to the other, so the bond is ionic. If only non-metals join, they share electrons instead, so the bond is covalent. If only metals are present, their ions sit in a shared sea of electrons, so the bond is metallic. Name the elements first, decide whether electrons are transferred, shared or pooled, and the bond type follows.

Match the particle to its property

Which bond forms?

Sodium, a metal, reacts with chlorine, a non-metal, to form sodium chloride. Which type of bonding holds it together?

• Ionic bonding.
• Covalent bonding.
• Metallic bonding.
• No bonding at all.

The periodic table

Select the TWO true statements about the periodic table.

• The columns are called groups
• Elements in the same group have similar properties
• The columns are called periods
• The metals are all on the right

Number of neutrons

An atom has a mass number of 23 and an atomic number of 11. The number of neutrons is the mass number minus the atomic number. Subtract to find the number of neutrons.

Order how an ionic bond forms

Put the steps of forming an ionic bond in order, earliest first.

• A metal atom loses one or more electrons
• The metal atom becomes a positive ion
• A non-metal atom gains those electrons
• The oppositely charged ions attract and bond

Complete the facts

The number of protons in an atom is its atomic _____. The protons plus the neutrons give the _____ number. A bond formed by transferring electrons from a metal to a non-metal is _____. A bond formed by non-metals sharing electrons is _____.

Match the bond type to how it works

Spot the true atom facts

Tap the TWO statements that are true about atoms and bonding.

• The atomic number is the number of protons
• Covalent bonding shares electrons between non-metals
• Electrons carry a positive charge
• Ionic bonding joins two non-metals

Identify the bonding

Read each case and choose the best response, with a reason.

• Two non-metal atoms, oxygen and hydrogen, join to form water. Which type of bonding is this?
• A block of pure copper conducts electricity because of its bonding. What holds a metal like copper together?
• A student says an atom with mass number 16 and atomic number 8 has 16 neutrons. How should this be corrected?

Explain structure and bonding

A student is studying sodium chloride and water. Explain the structure of an atom and how the bonding differs between these two substances.

• Name the three particles in an atom and their charges
• Explain what the atomic number and mass number are
• Explain the ionic bonding in sodium chloride
• Explain the covalent bonding in water
• Finish by explaining how the periodic table is arranged