Chemistry — Autumn PLC Extras

What is an electron shell?

A region around the nucleus where electrons are found

How are electrons arranged in an atom?

In shells around the nucleus

How many electrons can the first electron shell hold?

2

How many electrons can the second electron shell hold?

8

How many electrons can the third electron shell hold?

8

What does the electronic structure of an atom show?

How its electrons are arranged in shells

Why are noble gases unreactive?

They have a full outer electron shell

How did Mendeleev arrange the elements in his periodic table?

By atomic mass

Why did Mendeleev leave gaps in his periodic table?

He predicted that undiscovered elements would fill the gaps

Why was Mendeleev's periodic table better than earlier versions?

He arranged elements with similar properties into groups and left gaps for undiscovered elements

What determines the position of an element in the modern periodic table?

Its atomic number

How is the periodic table linked to electronic structure?

Elements in the same group have the same number of outer shell electrons

What happens to the number of electron shells as you move down a group?

It increases

What happens to the reactivity of Group 1 metals down the group?

They become more reactive

What happens to the reactivity of Group 7 elements down the group?

They become less reactive

Why do Group 1 metals become more reactive down the group?

The outer electron is further from the nucleus and easier to lose

Why do Group 7 elements become less reactive down the group?

The outer shell is further from the nucleus so it is harder to gain an electron

What are the three states of matter?

Solid liquid and gas

How are particles arranged in a solid?

Closely packed in fixed positions

How are particles arranged in a liquid?

Close together but able to move past each other

How are particles arranged in a gas?

Far apart and moving randomly

What happens to particles when a substance is heated?

They gain kinetic energy

What is the difference between melting and boiling?

Melting changes a solid to a liquid while boiling changes a liquid to a gas

What happens when an atom becomes an ion?

It gains or loses electrons

How does an atom form a positive ion?

It loses electrons

How does an atom form a negative ion?

It gains electrons

What is metallic bonding?

The attraction between positive metal ions and delocalised electrons

Why can metals conduct electricity?

They contain delocalised electrons that can move

Why can metals conduct thermal energy?

Delocalised electrons transfer energy through the structure

Why are metals malleable?

Layers of metal ions can slide over each other while the metallic bonds remain

What is a giant metallic structure?

A regular lattice of positive metal ions surrounded by delocalised electrons