3.4 Periodic Trends Flashcards
Which has a higher electronegativity out of Ca and Br?
Explain why
Bromine
Both have the same number of electron shells (4), so have the same amount of shielding and the bonding pairs are the same distance from the nucleus. Br has a greater nuclear charge therefore has a greater attraction to the pair of bonding electrons. (Higher electronegativity)
Which has a lower electronegativity out of Li and K?
Explain why
Potassium
K has two extra shells, so it experiences more shielding and has a greater distance between the nucleus and bonding electrons. Although it has a greater nuclear charge than Li it has less attraction for the pair of bonding electrons. (Lower electronegativity)
Which has a higher first ionisation energy:
C or O?
Explain why
Oxygen
Both have the same number of electron shells (2), so have the same amount of shielding and the bonding pairs are the same distance from the nucleus. O has a greater nuclear charge therefore more energy is required to remove electrons from O compared to C (higher first ionisation energy)
Which has a lower first ionisation energy:
N or P?
Explain why
Phosphorous
P has an extra shell, so it experiences more shielding and has a greater distance between the nucleus and bonding electrons. Although it has a greater nuclear charge than N, P requires less energy to remove electrons compared to N so has a lower first ionisation energy.
Which has a bigger radius:
O or N?
Explain why
Nitrogen
Both have the same number of electron shells (2), so have the same amount of shielding. N has a smaller nuclear charge, therefore it does not pull the valence electrons in as close, and therefore has a bigger radius
Which has a bigger radius:
Cl or Cl- ?
Explain why
Chloride ion (Cl-)
The nuclear charge is the same in Cl and Cl-. Cl- has an extra electron, so there is greater repulsion and Cl- is bigger
Which has the bigger radius?
Na or Na+ ?
Explain why
Sodium (Na)
Na+ has lost a whole electron shell, so it is smaller than Na
Which has the smaller radius:
O or O2- ?
Explain why
Oxygen
The nuclear charge is the same in O and O2-. O has two less electrons, so there is less repulsion and O is smaller
Which has the smaller radius:
Mg or Mg2+ ?
Explain why
Magnesium ion (Mg2+)
Mg2+ has lost a whole electron shell, so it is smaller than Mg
Which has a lower first ionisation energy:
Na or Al ?
Explain why
Sodium
Both have the same number of electron shells (3), so have the same amount of shielding and the bonding pairs are the same distance from the nucleus. Al has a greater nuclear charge therefore more energy is required to remove electrons from Al compared to Na. Na has a lower first ionisation energy.
Which has a lower first ionisation energy:
O or S ?
Explain why
Sulfur
S has an extra shell, so it experiences more shielding and there is a greater distance between the nucleus and bonding electrons. Although it has a greater nuclear charge than O, less energy is required to remove electrons from S compared to O. S has a lower first ionisation energy.
Which has a lower electronegativity:
Be or Ca ?
Explain why
Calcium
Ca has two extra shells, so it experiences more shielding and has a greater distance between the nucleus and bonding electrons. Although it has a greater nuclear charge than Ca, it has less attraction for the pair of bonding electrons. (Lower electronegativity)
Which has a lower electronegativity:
Si or S ?
Explain why
Silicon
Both have the same number of electron shells (3), so have the same amount of shielding and the bonding pairs are the same distance from the nucleus. Si has a smaller nuclear charge therefore has less of an attraction to the pair of bonding electrons. (Lower electronegativity)
Which has a higher electronegativity:
Mn or Cu ?
Explain why
Copper
Both have the same number of electron shells (4), so have the same amount of shielding and the bonding pairs are the same distance from the nucleus. Cu has a bigger nuclear charge therefore has more of an attraction to the pair of bonding electrons. (Higher electronegativity)
