Topic 1: Atomic Structure and the Periodic Table Flashcards
Hydrogen, deuterium and tritium are all isotopes of each other.
Identify one similarly and one difference between these isotopes. [2]
Similarity:
1. They’ve all got the same number of protons/electrons;
Differences:
2. They all have different numbers of neutrons
Hydrogen, deuterium and tritium are all isotopes of each other.
2
Deuterium can be written as 1H. Determine the number of protons, neutrons and electrons. [1]
- 1 proton, 1 neutron, 1 electron
Hydrogen, deuterium and tritium are all isotopes of each other.
Write the nuclear symbol for tritium, given that it has 2 neutrons. [1]
- 3
H
1
Explain why the relative atomic mass of copper (2 isotopes) is not a whole number. [2]
- A sample of copper is a mixture of isotopes in different abundances;
- The relative atomic mass is an average mass of these isotopes which isn’t a whole number
Give the electron configuration of a Cu atom (29 electrons)
1s2 2s2 2p6 3s2 3p6 3d10 4s1
What happens in an atom when energy is emitted? [2]
- Electrons move;
- From higher to lower energy levels
Explain why the lines in a set of lines on an emission spectrum get closer together as you go along. [1]
- The energy levels (shells) get closer together with increasing energy
What happens when an electron moves from a higher to a lower quantum shell? [1]
- Energy is released/emitted
Describe what the lines on an emission spectrum show. [1]
- Frequencies of light emitted when an electron drops to a lower energy level
Explain how emission spectra provide evidence that supports our current understanding of electrons existing in fixed energy levels [2]
- Emission spectra show that specific amounts of energy are emitted when electrons drop down from higher energy levels to lower energy levels;
- In-between amounts of energy are never emitted, which suggests that electrons only exist at very specific energy levels (they’re discrete)
Write an equation, including state symbols, to represent the first ionisation energy of carbon (C). [2]
C(g) —) C+(g) + e-
- Correct equation;
- Correct state symbols
Explain why increasing nuclear charge increases first ionisation energies. [2]
- As the nuclear charge increases there is a stronger force of attraction between the nucleus and the electron;
- So more energy is needed to remove the electron
Why does it take more energy to remove each successive electron? [2]
- The electrons are being removed from an increasingly positive ion;
- and there’s less repulsion among the remaining electrons so they’re held more strongly by the nucleus
What causes the sudden increases in ionisation energy? [1]
- When an electron is removed from a different shell there is a big increase in the energy required (since that shell is closer to the nucleus)
Explain why the melting point of sulphur is higher than that of phosphorus. [2]
- Sulphur (S8) has more electrons than phosphorus (P4);
- Which results in stronger London forces of attraction between molecules
What does emission spectroscopy provide evidence for the existence of? [1]
- Quantum shells
What is the electronic configuration for the S2- ion? (S = 16e) [1]
- 1s2 2s2 2p6 3s2 3p6
Which is the most likely sequence of values, in kJ mol-1, for the first four ionisation energies of barium?
A 1000 2251 3361 4564
B 496 4563 6913 9544
C 503 965 3458 4530
D 578 1817 2745 11578 [1]
- C
Which list contains only s-block elements?
A Li, Na, Mg, Cl
B K, Ca, Co, Rb
C Mg, Al, Sr, Ba
D Be, Rb, Ba, Ra [1]
- D
What is the electronic configuration of the arsenide ion, As3-? (As = 33e) [1]
- 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6
What is the total number of electrons in all the occupied p orbitals in a chloride ion, Cl-? (Cl = 17e) [1]
- 12
How many of each subatomic particle are there in oxygen-18? [1]
- 8 protons, 10 neutrons, 8 electrons