National 5 Unit 1 – Chemical Changes & Structure

These flashcards cover key concepts and terms from the National 5 Chemistry examination notes, focusing on reaction rates, atomic structure, bonding, and calculations.

The rate of a chemical reaction is a measure of how fast a reaction __________.

occurs.

Increasing the __________ means that there are more particles to collide and react.

concentration.

As the __________ increases, the rate of reaction increases.

temperature.

A __________ is a substance that speeds up a reaction without being consumed.

catalyst.

The charge of a proton is __________.

+1.

Electrons are found __________ the nucleus of the atom.

orbiting.

Isotopes have the same __________ but different mass numbers.

atomic number.

The __________ number is the total number of protons and neutrons in an atom.

mass.

Covalent bonds form when atoms __________ electrons to achieve stable electron configurations.

share.

Ionic bonds occur due to the __________ attraction between positively and negatively charged ions.

electrostatic.

The elements in the same __________ of the periodic table have similar chemical properties.

group.

The formula for water is __________.

H2O.

The average rate of a reaction can be calculated using the change in __________ divided by the change in time.

quantity.

Decreasing the __________ size increases the rate of reaction by providing more surface area.

particle.

Chemical formulas provide information about the __________ of elements in a substance.

ratio.

A covalent network substance has __________ melting and boiling points.

high.

The common unit for measuring average reaction rate is __________.

cm3 s-1.

Covalent molecular substances are usually __________ at room temperature.

liquid or gas.

The atomic number tells us the number of __________ in an atom.

protons.

Hydrogen bromide is an example of a molecule with a __________ shape.

linear.

Ionic substances only conduct electricity when they are __________ or dissolved in solution.

molten.

The mass number of an element indicates the total number of __________ and neutrons.

protons.

The first energy level in an atom can hold __________ electrons.

2.

Group 1 elements are known as __________ metals.

alkali.

The term __________ refers to the number of bonds an atom can make.

valency.

Chemical equations show the __________ and products involved in a reaction.

reactants.

Covalent bonds can be formed by the overlap of __________ pairs of electrons.

shared.

The shape of a molecule can affect its __________ and reactivity.

properties.

Substances like silicon dioxide have __________ structures with strong covalent bonds.

network.

A balanced chemical equation shows the __________ number of each type of atom on both sides.

same.

In a reaction involving hydrochloric acid and magnesium, magnesium produces __________ gas.

hydrogen.

The isotopes of carbon are denoted as __________ and 14C.

12C.

The boiling point of water is __________ degrees Celsius under normal atmospheric pressure.

100.