1.2 - Basic Ideas about Atoms

Question 1

Half-Life

Answer 1

The time it takes for the radioactivity of an isotope to drop to half of its initial value.

Question 2

Radiocarbon Decay

Answer 2

It is possible to use its half-life to determine the age of the sample by measuring the amount of carbon-14 left.

Question 3

Medical Applications of Radioactive Decay

Answer 3

• Cobalt-60 gamma rays used to penetrate and kill cancer cells
• Strontium-90 beta radiation is used to kill skin cancer
• Sterilising surgical instruments with gamma rays

Question 4

Medical Tracers - Radioisotopes

Answer 4

Monitoring the activity of the thyroid gland by having a patient drink iodine-131

Question 5

Standard Molar Ionisation Energy

Answer 5

The amount of energy needed to remove one mole of electrons from one mole of gaseous atoms (KJMol⁻¹)

Equation: M₍g₎ → M⁺ + e⁻

Question 6

Ionisation Energy Patterns

Answer 6

Across a period? = Increases
Increasing nuclear charge across the period requires more energy to remove 1 electron in the same shell.

Down a group? = Decreases
Increasing the distance between the nucleus and the outer shell, there is less attraction making it easier to remove an electron.

Question 7

Shape of Orbitals - S Oribital

Answer 7

Sphere

Question 8

Shape of Orbitals - P Orbital

Answer 8

Dumbell