Elements, Compounds, and Mixtures Quiz

What is an element?

• A pure substance made from only one type of atom

• A mixture of different atoms

• A compound of two or more elements

• A solution of metals

Answer explanation

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

How many chemical elements are there?

• 118

• 50

• 200

• 4

Answer explanation

There are 118 known chemical elements in the periodic table, making 118 the correct answer. The other options, 50, 200, and 4, do not accurately represent the total number of elements.

What is the periodic table?

• A table that lists all chemical elements

• A chart of all known mixtures

• A list of all known compounds

• A diagram of atomic structures

Answer explanation

The periodic table is a systematic arrangement of all chemical elements, organized by their atomic number, electron configuration, and recurring chemical properties. It does not list mixtures, compounds, or atomic structures.

Where are metals found on the periodic table?

• On the right

• In the middle and left

• Only at the top

• Only at the bottom

Answer explanation

Metals are primarily located in the middle and left sections of the periodic table. This area includes groups 1, 2, and the transition metals, which are known for their metallic properties.

What is a compound?

• A type of metal

• A single element

• A mixture of elements and compounds

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

Answer explanation

A compound is defined as a pure substance formed when two or more elements chemically bond together. This distinguishes it from mixtures and single elements, making the correct choice the one that describes this chemical bonding.

What is a mixture?

• A chemical bond between elements

• A combination of elements or compounds not chemically bonded

• A single type of atom

• A pure compound

Answer explanation

A mixture is defined as a combination of elements or compounds that are not chemically bonded. This distinguishes it from pure substances, which are either single types of atoms or compounds.

Which element is used to make electrical wires?

• Gold

• Iron

• Copper

• Aluminium

Answer explanation

Copper is the most widely used material for electrical wires due to its excellent conductivity, flexibility, and resistance to corrosion. While gold and aluminum are also used, copper remains the standard choice for most applications.

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 table salt, and O2 is oxygen gas.

What technique can separate a mixture of sand and water?

• Thermal decomposition

• Electrolysis

• Filtration

• Crystallisation

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 smallest particle of an element?

• Mixture

• Atom

• Compound

• Molecule

Answer explanation

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