Trends in the ionisation energies across period 3 quiz

1. What is the definition of first ionisation energy?

a) Energy released when an electron is added to an atom in the gas state
b) Energy required to remove 1 mole of electrons from 1 mole of gaseous atoms
c) Energy released when an atom gains a proton
d) Energy required to remove 1 mole of protons from an atom

2. The general trend in first ionisation energy across Period 3 is:

a) It decreases due to increasing atomic radius
b) It increases due to increasing nuclear charge
c) It stays constant
d) It decreases due to increased shielding

3. Which three factors determine the size of ionisation energy?

a) Nuclear charge, atomic radius, shielding
b) Nuclear charge, density, mass number
c) Atomic radius, melting point, shielding
d) Electron affinity, electronegativity, melting point

4. Ionisation energy increases across a period in the periodic table because the charge increase and shielding stays roughly the same.

5. Why is there a drop in ionisation energy from Mg to Al?

a) Aluminium has a higher nuclear charge
b) Aluminium has fewer protons
c) Aluminium has a half-filled p sub-shell
d) Electron removed from Al is from a 3p orbital which is higher in energy

6. There is a in the ionisation energy when we move from the elements phosphorus to sulfur, this is due to the fact that the electron which is removed from sulfur experiences extra due to pairing and so requires less energy to remove it.

7. From which orbital is the electron removed from when magnesium is first ionised?

a) 2p
b) 3s
c) 3p
d) 4s

8. When aluminium is first ionised the electron which is removed is in a orbital.

9. In phosphorus the 3p electrons:

a) Are all paired in the same orbital
b) Are all paired in different orbitals
c) Occupy separate orbitals with parallel spins
d) Have opposite spins in each orbital

10. Hund's Rule states:

a) Electrons fill the lowest energy orbitals first
b) Electron pair up before filling empty orbitals
c) The number of protons is the same as the number of electrons in ions
d) Electrons occupy separate orbitals with parallel spins before pairing up

11. Which factor does not change significantly across a period?

a) Shielding
b) Nuclear charge
c) Atomic radius
d) Effective nuclear charge

12. The general trend in atomic radius across period 3 elements is that the size of the atoms , this is due to an increase in the size of the charge pulling the electrons closer.

13. Which of the elements below has the lowest first ionisation energy?

a) Sodium
b) Aluminium
c) Magnesium
d) Phosphorus

14. The electron removed from sulfur during its first ionisation is:

a) From a 3s orbital
b) From a 4s orbital
c) From a 3p orbital
d) From a 2p orbital

15. Shielding in atoms is a result of the inner electrons creating a barrier or shield between the nucleus and the outer or valence electrons. This shielding reduces the effective charge experienced by the valence electron.