Atomic structure and the periodic table - questions 1-20

What is an atom?

An atom is the smallest part of an element that can exist.

What is an element?

Elements are made from one type of atom.

What is a compound?

Compounds are made from two or more elements which are chemically bonded.

How do you name a compound with 2 elements?

The first name is the metal element and the surname is the non metal.

How do you name a compound with 3 elements, one of which is oxygen?

The ending is -ate. E.g sodium carbonate.

What is the conservation of mass?

In a chemical reaction, no atoms are made or destroyed, so the mass of reactants = mass of products.

What is a mixture?

A mixture consists of two or more elements or compounds not chemically bonded together.

How could you separate an insoluble solid from a mixture?

By filtration.

How could you separate a soluble solid from a mixture?

Crystallisation.

What do the following state symbols mean : (g), (l), (s), (aq)?

Solid, liquid, gas, aqueous/ formed a solution.

What is distillation used to separate?

Two or more liquids with different boiling points.

Name the two changes of state in distillation.

The liquid evaporates when heated, the gas is then cooled and condenses back into a liquid.

Describe the method to separate two liquids by distillation.

Heat the mixture in a round bottom flask. The liquid with the lowest boiling point will boil first. This liquid will evaporate and turn into a gas and enter the condenser. In the condenser, the gas will cool and then condense. The liquid is collected in the beaker and the other liquid will be left in the flask.

What is chromatography used to separate?

Chromatography is used to separate mixtures of more than one soluble substance dissolved in solution.

Why is the start line drawn in pencil?

Because pencil is insoluble and will not run.

Why muse the solvent be below the start line?

So that the mixture does not dissolve into the solvent but instead is carried up the paper.

Name the three subatomic particles.

Electrons, protons and neutrons.

What is found in the nucleus of the atom?

Protons and neutrons.

Where are the electrons found?

They orbit the nucleus in electron shells.

State the charges of the subatomic particles.

Protons: +1, electrons: -1, neutrons: no charge.