Module 2 chemistry

Dr B

Relative charge, mass and location of a proton?

• 1+

• 1

• Nucleus

Relative charge, mass and location of an neutron?

• 0

• 1

• Nucleus

Relative charge, mass and location of an electron?

• 1-

• 1/1836

• orbitals

Define isotopes

They are atoms of the same element with a different number of neutrons

Meaning of A and Z symbol for element

• A= mass no (total no of protons and neutrons in nucleus)

• Z= atomic number (total no of protons in nucleus)

Why do atoms have the same number of protons and electrons?

Because they are neutral

Define an orbital

It is a region of space around the nucleus that can hold up to 2 electrons with opposite spins

• How many electrons can s-orbitals hold

• What are their shape

• How many s-subshells do each shell contain

• How many electrons can s-subshells hold

• 2 electrons

• Spherical

• 1 s-subshell

• Can hold 2 electrons (1s2)

• How many electrons can p-orbitals hold

• What are their shape

• Which energy levels contain a p-subshell?

• How many p-orbitals are found in p-subshells?

• How many electrons can p-subshells hold

• 2 electrons

• Dumbbell

• Energy levels 2-4

• 3 p-orbitals

• 6 electrons (eg. 1s2s2 2p6)

• How many electrons can d-orbitals hold

• How many d-orbitals are found in d-subshells?

• Which energy levels contain a d-subshell?

• How many electrons can d-subshells hold

• 2 electrons

• 5 d-orbitals

• Energy levels 3 and 4

• 10 electrons

• How many electrons can f-orbitals hold

• How many f-orbitals are found in f-subshells?

• Which energy levels contain a f-subshell?

• How many electrons can d-subshells hold

• 2 electrons

• 7 f-orbitals in f-subshells

• Energy level 4 contains one f-subshell

• 14 electrons (4f14)

Which energy subshell do electrons occupy first when added to atoms?

the lowest energy subshell

Explain how electrons fill orbitals within a subshell.

They occupy orbitals in subshells SINGLY before pairing up

Why is Chromium’s electron config 4s1 3d5?

This is because half filled d-orbitals (3d5) have extra stability

Why is Copper’s electron config 4s1 3d10?

because a fully filled d-orbital (3d¹⁰) provides extra stability

What happens when transition elements form ions?

The 4s electrons are lost before 3d.

eg. Fe+: 1s2 2s2 2p6 3s2 3p2 (4s2) 3d5

(a) What is meant by the term standard solution? (1)

A solution of known concentration