1: Atomic structure and periodic table

What is an atom?

The smallest part of an element that can exist

What is an element?

A substance made of only one type of atom

What is a compound?

Two or more elements chemically combined in fixed proportions

What is a mixture?

Two or more substances not chemically combined

How are compounds separated?

By chemical reactions

How are mixtures separated?

By physical processes like filtration or distillation

Give examples of separation techniques

Filtration crystallisation simple distillation fractional distillation chromatography

What is a chemical reaction?

A process where new substances are formed often with energy changes

What is the periodic table?

A table of elements arranged by atomic number

What is the atomic number?

The number of protons in an atom

What is the mass number?

The number of protons plus neutrons

What are isotopes?

Atoms of the same element with different numbers of neutrons

What is relative atomic mass?

The weighted average mass of an element’s isotopes

What is the charge of a proton?

+1

What is the charge of a neutron?

0

What is the charge of an electron?

-1

Where is most of the mass in an atom?

In the nucleus

What is the size of an atom?

About 0.1 nm (1 x 10^-10 m)

What is the plum pudding model?

Atom as a ball of positive charge with electrons embedded

What did the alpha scattering experiment show?

Atoms have a small dense positively charged nucleus

What did Niels Bohr suggest?

Electrons orbit at specific energy levels

Who discovered the neutron?

James Chadwick

What is electronic structure?

Arrangement of electrons in shells (e.g. 2

What determines an element’s reactivity?

The number of electrons in the outer shell

What is a group in the periodic table?

A column of elements with similar properties

What is a period?

A row in the periodic table

Where are metals found?

Left and centre of the periodic table

Where are non-metals found?

Right side of the periodic table

What do metals form?

Positive ions

What are Group 0 elements called?

Noble gases

Why are noble gases unreactive?

They have full outer electron shells

What happens to boiling point in Group 0 down the group?

It increases

What are Group 1 elements called?

Alkali metals

What is special about Group 1 outer electrons?

They have one outer electron

What happens to reactivity in Group 1 down the group?

It increases

What are Group 7 elements called?

Halogens

What is special about Group 7 outer electrons?

They have seven outer electrons

What happens to reactivity in Group 7 down the group?

It decreases

What happens to boiling point in Group 7 down the group?

It increases

What is a displacement reaction?

A more reactive element replaces a less reactive one

What are transition metals?

Metals in the centre of the periodic table

How do transition metals compare to Group 1?

Higher melting points denser stronger less reactive

What are typical properties of transition metals?

Form coloured compounds have multiple ion charges act as catalysts

Give examples of transition metals

Iron copper nickel cobalt chromium manganese