Chemistry C1: Structures, Trends and Quantitative Chemistry

What everything is made of

Every substance is built from atoms. An atom has a tiny central nucleus, which holds particles called protons and neutrons, surrounded by electrons that sit in shells. A proton carries a positive charge, a neutron carries no charge, and an electron carries a negative charge. The number of protons is called the atomic number, and it decides which element an atom is. The elements are arranged in the periodic table in order of atomic number, and their position tells you a great deal about how they behave. Atoms join together by bonding, either by transferring electrons or by sharing them, and we can work out the mass of a substance by adding up the masses of its atoms. This module covers atomic structure, the periodic table and its trends, bonding, and how to find a relative formula mass.

Atomic structure words

Learn these terms before the periodic table is read. They name the particles and how atoms are described.

Match each particle to its description

Metals against non-metals

The periodic table splits into metals and non-metals, and knowing which is which lets you predict how an element behaves.

Where is this element on the table?

An element is in Group 1 of the periodic table. What does its group number tell you?

• It has one electron in its outer shell
• It has only one shell in total
• It is a non-metal
• It is completely unreactive

Read the group, know the element

The periodic table is not a random grid: its layout is a code you can read. The group, which is the column, tells you the number of electrons in an element outer shell, and because that drives how an element reacts, elements in the same group behave alike. The period, which is the row, tells you how many shells the atoms have. The side tells you metal or non-metal. So you do not have to memorise every element one by one. When a question gives you an element and its position, use the position first: the group for the outer electrons and the reactivity, the period for the number of shells, and the side of the table for whether it is a metal. Reading the table is faster and more reliable than trying to remember it.

Pick the true statements about the periodic table

Select every statement about the periodic table that is true.

• Elements are arranged in order of atomic number
• A group is a column of elements with similar properties
• Metals are on the left and middle
• Every element is a gas
• The period number gives the number of protons

Order the steps to find a relative formula mass

Put the steps of finding a relative formula mass in order.

• Identify each type of atom in the substance
• Find the relative atomic mass of each from the periodic table
• Multiply each atomic mass by how many of that atom there are
• Add all the totals together
• The sum is the relative formula mass

Complete the atomic-structure facts

The centre of an atom is the _____. A positive particle found in it is a _____. The number of protons is the _____. A column of the periodic table is a _____.

Work out the relative formula mass

A substance is made of one carbon atom and two oxygen atoms. Carbon has a relative atomic mass of 12 and oxygen has a relative atomic mass of 16. Add the masses to work out the relative formula mass of the substance.

A library and its shelves

Walk into a well-run library and you can find any book without knowing the whole collection, because everything has a place. Stories in one area, science in another, and within each area the books run in a sensible order. The periodic table works the same way. Each element sits in a spot that tells you about it: which family it belongs to, how many layers of electrons it carries, and whether it behaves like a metal. Once you learn to read the position, you do not need to memorise every element, any more than a librarian memorises every book on the shelves. The order does the remembering for you, and your job is simply to read it.

Tap the two ionic bonding statements

Tap the TWO statements that are true of ionic bonding.

• it forms between a metal and a non-metal
• electrons are transferred from one atom to another
• electrons are shared between two non-metals
• it happens only between two metals

Classify each element or bond

Read each situation and choose the best answer.

• An element is shiny, conducts electricity, and sits on the left of the periodic table. What is it likely to be?
• A metal reacts with a non-metal and electrons are transferred from one to the other. What type of bonding is this?
• Two non-metals join together by sharing electrons. What type of bonding is this?

Build a bonding sentence

Choose the word for each gap to complete one point about bonding.

Explain atoms, the table and bonding

A friend finds chemistry confusing and thinks the periodic table is just a random grid. Using what you have learned, explain how atoms are built, how the periodic table is organised, and how atoms bond.

• Explain the parts of an atom and where they are
• Explain how the periodic table is arranged into groups and periods
• Explain what the group number tells you about an element
• Explain the difference between ionic and covalent bonding
• Explain what relative formula mass is and how it is found