IGCSE Chemistry 0620 ON 24 V41

State which of the processes A to H: (a) happens when an acid reacts with an alkali

• D (neutralisation)

• A (oxidation)

• F (precipitation)

• H (combustion)

State which of the processes A to H: (b) reaches a position of equilibrium

• F (reversible reaction)

• A (irreversible reaction)

• C (combustion)

• G (decomposition)

State which of the processes A to H: (c) involves particles changing from fixed positions to being mobile, but still touching

• C (melting)

• A (sublimation)

• E (condensation)

• G (freezing)

State which of the processes A to H: (d) are physical changes

• B (diffusion) and C (melting)

• A (rusting) and D (burning)

• E (fermentation) and F (photosynthesis)

• G (respiration) and H (combustion)

State which of the processes A to H: (e) is caused by gas particles colliding with each other.

• B (diffusion)

• A (evaporation)

• C (condensation)

• D (sublimation)

This question is about atomic structure and the Periodic Table. (a) Define the term nucleon number.

• The nucleon number is the total number of protons and neutrons in the nucleus of an atom.

• The nucleon number is the number of electrons in the outer shell of an atom.

• The nucleon number is the number of protons in the nucleus of an atom.

• The nucleon number is the atomic number of an element.

State the connection between the number of occupied electron shells in an atom and the period number of that element.

• The number of occupied electron shells in an atom is equal to the period number of that element.

• The number of occupied electron shells in an atom is equal to the group number of that element.

• The number of occupied electron shells in an atom is always one less than the period number of that element.

• The number of occupied electron shells in an atom is double the period number of that element.

This question is about atomic structure and the Periodic Table. (c) Write the electronic configuration of the following atom and ion.

• 28/14 Si: 2, 8, 4 37/17 Cl⁻: 2, 8, 8, 8

• 28/14 Si: 2, 8, 8 37/17 Cl⁻: 2, 8, 7, 8

• 28/14 Si: 2, 8, 2, 2 37/17 Cl⁻: 2, 8, 8, 7

• 28/14 Si: 2, 8, 6 37/17 Cl⁻: 2, 8, 8, 6

This question is about atomic structure and the Periodic Table. (d) Complete Table 2.1. Table 2.1: | atom or ion | number of protons | number of neutrons | number of electrons | | 23/11 Na | 11 | ___ | ___ | | 19/9 F⁻ | 9 | 10 | ___ | | ___ | 31 | 38 | 28 |

• 23/11 Na: 12 neutrons, 11 electrons 19/9 F⁻: 10 electrons 31/13 Al: (Aluminum-31): 13 protons, 18 neutrons, 13 electrons

• 23/11 Na: 10 neutrons, 12 electrons 19/9 F⁻: 9 electrons 31/13 Al: (Aluminum-31): 12 protons, 19 neutrons, 14 electrons

• 23/11 Na: 11 neutrons, 12 electrons 19/9 F⁻: 11 electrons 31/13 Al: (Aluminum-31): 14 protons, 17 neutrons, 12 electrons

• 23/11 Na: 13 neutrons, 10 electrons 19/9 F⁻: 8 electrons 31/13 Al: (Aluminum-31): 15 protons, 16 neutrons, 15 electrons

Define the term isotopes.

• Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons.

• Isotopes are atoms of different elements with the same number of protons and neutrons.

• Isotopes are atoms of the same element with different numbers of protons and electrons.

• Isotopes are atoms of the same element with the same number of neutrons but different numbers of protons.