1) Periodicity Flashcards
How is the modern periodic table arranged?
By increasing atomic number.
What 3 factors affect ionisation energy?
- Atomic radius.
- Nuclear charge.
- Electron shielding.
How does atomic radius affect ionisation energy?
The greater the distance between the nucleus and the outer electrons, the less the nuclear attraction.
How does nuclear charge affect ionisation energy?
The more protons there are in the nucleus of an atom, the greater the attraction between the nucleus and the outer electrons.
How does electron shielding affect ionisation energy?
Inner-shell electrons repel outer-shell electrons. This repulsion reduces the attraction between the nucleus and the outer electrons.
What’s the trend in first ionisation energy down a group?
- Atomic radius increases.
- More inner shells so shielding increases.
- Nuclear attraction on outer electrons decreases.
- First ionisation energy decreases.
What’s the trend in first ionisation energy across a period?
- Nuclear charge increases.
- Same shell: similar shielding.
- Nuclear attraction increases.
- Atomic radius decreases.
- First ionisation energy increases.
Define metallic bonding.
-Metallic bonding is the strong electrostatic attraction between delocalised electrons and positive ions.
State which two elements from the first twenty elements of the modern periodic table are not arranged in order of increasing atomic mass.
Potassium and argon.
Why does the modern Periodic Table not arrange some elements, such as potassium and argon in order of increasing atomic mass?
Because they are arranged in increasing atomic number.
Explain the decrease in the atomic radii across the period from Na to Cl.
- Nuclear charge increases.
- Electrons are added to the same shell.
- Therefore greater attraction.
Explain why first ionisation energies show a general increase across Period 3.
- Atomic radius decreases.
- Electrons are added to the same shell.
- The number of protons in the nucleus increases.
- Nuclear attraction increases.
Write an equation, including state symbols, to represent the third ionisation energy of sodium. Use ‘Periodicity’ card to test knowledge.
Rate knowledge 1-5.
Explain why less energy is needed to ionise gaseous atoms of rubidium than gaseous atoms of sodium.
- Rb has more shells.
- Rb has more shielding.
- Therefore there’s less attraction.
Why do caesium and barium have different atomic numbers?
They have different numbers of protons.
