Elements, Compounds, and Mixtures - BBC BITESIZE Quiz

What is an element?

• A pure substance made from only one type of atom.

• A compound of two or more elements.

• A solution of various substances.

• A mixture of different atoms.

Answer explanation

An element is defined as a pure substance made from only one type of atom, distinguishing it from compounds, solutions, and mixtures which involve multiple types of atoms or substances.

How many chemical elements are there?

• 200

• 150

• 118

• 94

Answer explanation

There are currently 118 confirmed chemical elements in the periodic table, ranging from hydrogen (atomic number 1) to oganesson (atomic number 118). Therefore, the correct answer is 118.

Where are metals found on the periodic table?

• In the middle and on the left

• Scattered throughout

• On the right

• Only at the bottom

Answer explanation

Metals are primarily located in the middle and on the left side of the periodic table, including groups 1-12. This distinguishes them from nonmetals, which are found on the right.

What is the formula for water?

• H2O

• CO2

• NaCl

• O2

Answer explanation

The formula for water is H2O, which indicates that each molecule consists of two hydrogen atoms and one oxygen atom. The other options represent different compounds: CO2 is carbon dioxide, NaCl is salt, and O2 is oxygen.

Which element is used to make electrical wires due to its conductivity?

• Aluminium

• Copper

• Gold

• Iron

Answer explanation

Copper is the most widely used material for electrical wires due to its excellent conductivity, making it more efficient than aluminium, gold, or iron for transmitting electricity.

What is a compound?

• A pure substance made from two or more elements chemically bonded.

• A mixture of elements and compounds.

• A single element in its pure form.

• A solution of various substances.

Answer explanation

A compound is defined as a pure substance formed when two or more elements are chemically bonded together. This distinguishes it from mixtures and single elements, making the first answer choice the correct one.

What technique can separate a mixture of sand and water?

• Electrolysis

• Crystallisation

• Filtration

• Thermal decomposition

Answer explanation

Filtration is the technique used to separate a mixture of sand and water. The sand particles are trapped by the filter, while the water passes through, effectively separating the two components.

What is the main component of the air we breathe?

• Carbon dioxide

• Hydrogen

• Nitrogen

• Oxygen

Answer explanation

The air we breathe is primarily composed of nitrogen, which makes up about 78% of the atmosphere. Oxygen, while essential for life, constitutes only about 21%. Therefore, nitrogen is the main component of the air.

What is the smallest particle of an element?

• Molecule

• Compound

• Mixture

• Atom

Answer explanation

The smallest particle of an element is an atom. Atoms are the basic building blocks of matter, while molecules are made of two or more atoms, compounds consist of different elements, and mixtures are combinations of substances.

Which element is known for its 'squeaky pop' sound when ignited?

• Nitrogen

• Hydrogen

• Oxygen

• Helium

Answer explanation

Hydrogen is known for its 'squeaky pop' sound when ignited due to the rapid combustion of hydrogen gas, which produces water vapor and releases energy, creating a distinct popping noise.