Flashcards
3.1.4- EVIDENCE FOR ELECTRON SHELLS
Cards in this deck (17)
- 1What is ionisation?Ionisation occurs when atoms gain or lose electrons.
- 2What is the general equation for ionisation?Xe (g) -> Xe+ (g) + e-.
Ne (g) -> Ne+ (g) + e-. - 3What is a mixture of these ions called?A plasma.
- 4What is first ionisation energy?The energy required to remove one electron from each atom in one mole of gaseous atoms, to make one mole of gaseous 1+ ions.
- 5What is first ionisation energy a measure of?How easily an atom loses an electron to form a 1+ ion.
- 6Which elecrons are removed first?Electorns in the outer shell are removed first as they experience the smallest nuclear attraction. The outer-shell electrons are furthest away from the nucleus and require the smallest ionisation energy,
- 7What 3 factors affect ionisation energy?Atomic radius, nuclear charge and electron shielding/ screening.
- 8How does atomic radius affect the ionisation energy?The larger the atomic radius, the smaller the nuclear attraction experienced by outer electrons. This is because the positive charge of the nucleus is essentially further away from the outer shell of electrons.
- 9How does nuclear charge affect the ionisation energy?The higher the nuclear charge, the larger the attractive force of the nucleus and the larger the ionisation energy.
- 10How does electron shielding/ screening affect the ionisation energy?Inner shells of electrons repel the outer-shell electrons because they are all negative. This repelling effect is electron shielding. The more inner shells there are, the higher the shielding effect and the smaller the the nuclear attraction experienced by outer electrons, resulting in a lower ionisation energy.
- 11What is successive ionisation?Vakues that are a measure of the energy required to remove each electron in turn.
- 12How many ionisation energies does an element have?The same number as the number of electrons it has.
- 13What are the equations for the 3 successive ionisation energies of lithium?Li (g) -> Li+ (g) + e-.
Li+ (g) -> Li2+ (g) + e-.
Li2+ (g) -> Li3+ (g) + e-. - 14How does each ionisation energy differ?Ecah successive ionisation energy is higher than the one before.
- 15Why is each successive ionisation energy larger than the one before?As each electron is removed, there is less repulsion and each shell will be drawn in slightly closer. The positive charge will outweigh the negative charge every time an electron is removed. As the distance of each electron from the nucleus drecreases slightly, the nuclear attraction increases and more energy is required to remove each successive electron.
- 16In a graph of successive ionisation energies, where will a big jump be seen?If an element has 5 electrons in its out shell, there will be a big jump between the 5th and 6th ionisation energy. This is because the first 5 electrons aer in the outer shell and the 6th is in the inner shell. As it is closer to the nucleus, more enrgy will be required to overcome the attraction.
- 17What does the big jump in successive ionisation energies tell you?The number of electrons in the outer shell.
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- AS - Level AS Chemistry (Module 3.1) Flashcards on 3.1.4- EVIDENCE FOR ELECTRON SHELLS, created by vittoria howard on 23/11/2016.
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