1.3 electron configuration Flashcards
Electron shells are split into…
4 subshells.
What are the 4 types of subshell?
s, p ,d and f
How many orbitals does the s subshell contain?
The s subshell contains 1 orbital and can hold 2 electrons.
How many orbitals does the p subshell contain?
The p subshell contains 3 orbitals and can hold 6 electrons.
How many orbitals does the d subshell contain?
The d subshell contains 5 orbitals and can hold 10 electrons.
How many orbitals does the f subshell contain?
The f subshell contains 7 orbitals and can hold 14 electrons.
For transition metals Cr and Cu the 3d subshell must be…
half full (5 electrons) or full (10 electrons).
What is ionisation energy?
Ionisation energy is the minimum amount of energy required to remove 1 mole of electrons from 1 mole of atoms in the gaseous state.
- Ionisation requires energy so they are always endothermic processes and have a positive value.
How does shielding affect ionisation energy?
Shielding is when there are more electron shells between the positive nucleus and the negative electron that is being removed. This means that less energy is required as there is a weaker attraction.
How does atomic size affect ionisation energy?
The bigger the atom the further away the outer electrons are from the nucleus. The attractive force between the nucleus and the outer electrons reduces meaning it is easier to remove electrons.
How does nuclear charge affect ionisation energy?
The more protons in the nucleus the bigger the attraction between the nucleus and outer electrons. This means more energy is required to remove the electron.
Define first ionisation energy.
The first ionisation energy is the enthalpy (energy) change when one mole of gaseous atoms forms one mole of gaseous ions with a single positive charge.
H(g) → H+(g) + e-
Explain the 1st ionisation trends of groups in the periodic table.
Ionisation energy decreases as we go down a group.
- ATOMIC RADIUS increases as we go down the group so outer electrons are further away from the nucleus so the attractive force is weaker therefore first ionisation energy decreases
- SHEILDING increases as we go down the group as there are more shells between the nucleus and the outer shell so the attractive force is weaker therefore ionisation energy decreases
Explain the 1st ionisation energy trends of periods in the periodic table.
Ionisation energy increases as we go across a period.
- INCREASING NUMBER OF PROTONS in the nucleus so therefore increases the nuclear attraction between outer electron and nucleus meaning ionisation energy increases.
What are the exceptions for increasing ionisation energy across a period?
In period 3, aluminium and sulfur show a decrease in ionisation energy which does not follow the pattern of increasing ionisation energies across a period.
Why does aluminium in period 3 have a lower ionisation energy than magnesium?
Aluminium has a lower ionisation energy because the outermost electron sits in a higher energy subshell slightly further away from the nucleus than the outer electron in magnesium.
- This decrease at aluminium is evidence for atoms having subshells.
Why does sulfur in period 3 have a lower ionisation energy than phosphorus?
Sulfur has 4 outer electrons in the 3p orbital meaning that removing an electron from sulfur involves taking it from an orbital with 2 electrons. We know that electrons repel each other so less energy is needed to remove an electron from an orbital with 2 electrons so it therefore will require less energy meaning that sulfur has a lower ionisation energy.
- This decrease at sulfur is evidence for electron repulsion in an oribital.
