GCSE Chemistry Atomic structure questions by topic

Copy and complete the table about the three subatomic particles.

1. (a)State the relative charge of a proton.[1]
2. (b)State the relative mass of an electron compared with a proton.[1]
3. (c)Name the particle in the nucleus that carries no charge.[1]

A neutral atom of potassium-41 is considered.

1. (a)Potassium has atomic number 19. State the number of protons in the atom.[1]
2. (b)Calculate the number of neutrons in potassium-41.[1]
3. (c)State the number of electrons in the atom.[1]

An atom of an element has the electronic structure 2,8,4.

1. (a)State the atomic number of the element.[1]
2. (b)State the group of the element.[1]
3. (c)State the period of the element.[1]

A small piece of lithium is dropped into a beaker of water with universal indicator.

1. (a)State one observation that shows a gas is being produced.[1]
2. (b)Name the gas.[1]
3. (c)State the colour the indicator turns.[1]
4. (d)State what this colour shows about the solution formed.[1]
5. (e)Name the compound dissolved in the water.[1]

This question is about the isotope sulfur-33, which has atomic number 16.

1. (a)State the number of protons in a sulfur-33 atom.[1]
2. (b)Calculate the number of neutrons in sulfur-33.[1]
3. (c)A sulfur atom gains two electrons to form the ion S²⁻. State the total number of electrons in this ion.[1]
4. (d)Sulfur also has an isotope, sulfur-32. Explain why the two isotopes behave identically in chemical reactions.[1]

Argon has atomic number 18 and is used to fill some double-glazed window panels.

1. (a)Write the electronic structure of an argon atom.[1]
2. (b)State the group and the period that argon occupies.[1]
3. (c)Explain why an argon atom does not form ions.[2]

Group 1 metals are stored under oil in the laboratory.

1. (a)Explain why Group 1 metals must be kept away from air and water.[2]
2. (b)Write the word equation for the reaction of sodium with oxygen.[1]
3. (c)Rubidium is below potassium in Group 1. Predict how its reaction with water compares with potassium’s, giving a reason.[1]

Chlorine water is added to a colourless solution of potassium bromide, and separately to a colourless solution of potassium iodide.

1. (a)State the colour change seen in the potassium bromide solution and name the substance causing it.[2]
2. (b)State the colour change seen in the potassium iodide solution.[1]
3. (c)Explain, in terms of reactivity, why chlorine reacts with both solutions.[1]

The model of the atom changed several times between 1800 and 1932.

1. (a)Name the scientist whose alpha-scattering experiment replaced the plum pudding model.[1]
2. (b)Describe what the alpha-scattering results showed about the structure of the atom.[2]
3. (c)Name the scientist who proposed that electrons occupy shells at fixed distances.[1]
4. (d)Name the particle whose discovery completed the modern model, and the year of its discovery.[1]

The elements sodium (2,8,1) and sulfur (2,8,6) sit in the same period of the periodic table.

1. (a)Explain, in terms of electrons, why both elements are in period 3.[1]
2. (b)Predict the charge of the ion formed by each element, giving a reason for each.[2]
3. (c)Classify each element as a metal or a non-metal and give one physical property of each.[2]

A sample of magnesium is analysed: 79% of its atoms are magnesium-24, 10% are magnesium-25 and 11% are magnesium-26.

1. (a)Work out the weighted mean mass of magnesium from these figures. Give your answer to 1 decimal place.[3]
2. (b)Explain why no single magnesium atom actually has the mass you calculated.[1]
3. (c)State one thing magnesium-24 and magnesium-26 atoms have in common, and one way they differ.[2]

After seeing the alpha-particle scattering experiment, a student writes: “Gold atoms must be solid spheres, because some alpha particles bounced back.”

1. (a)Most alpha particles passed straight through the foil. Explain what this shows about the atom.[2]
2. (b)A tiny fraction of the alpha particles were deflected backwards. Explain what this shows about the nucleus.[2]
3. (c)Rewrite the student’s conclusion so that it is correct.[1]

A sample of gallium contains 60% gallium-69 and 40% gallium-71.

1. (a)Calculate the relative atomic mass of gallium in the sample.[2]
2. (b)Explain why the periodic table value for gallium is not a whole number.[1]
3. (c)Explain why gallium-69 and gallium-71 have identical chemical properties.[1]

This question is about the noble gases (Group 0).

1. (a)Explain why the noble gases are unreactive.[2]
2. (b)Describe the trend in boiling points from helium to radon and explain it.[2]
3. (c)Xenon is heavier than argon. State which has the higher boiling point and justify the choice.[1]

Copper and potassium are both metals in period 4, but they could hardly be more different.

1. (a)Contrast the reactivity of copper and potassium with cold water.[2]
2. (b)Give three further properties that distinguish transition metals such as copper from Group 1 metals such as potassium.[3]
3. (c)Name one industrial process in which a transition metal or its compound acts as a catalyst.[1]

Element X has 20 protons; element Y has 17 protons and 18 neutrons in its most common isotope.

1. (a)Write the electronic structure of element X and state its group and period.[2]
2. (b)Calculate the mass number of element Y’s isotope and write its electronic structure.[2]
3. (c)Predict the formula of the compound formed between X and Y, explaining how each atom reaches a full outer shell.[2]

Aqueous sodium bromide is mixed with chlorine water. Chlorine sits above bromine in Group 7.

1. (a)Write the balanced symbol equation for the reaction.[2]
2. (b)Write the ionic equation for the same reaction.[1]
3. (c)Explain, in terms of electron transfer, why chlorine displaces bromine from the bromide ions.[2]
4. (d)Iodine water is added to a separate sample of aqueous sodium bromide. State and explain what is observed.[1]

Explain how the periodic table developed from Mendeleev’s arrangement into the modern one.

1. (a)Describe how Mendeleev arranged his table, and give two decisions of his that made it more convincing than a plain list of elements.[3]
2. (b)Explain why the modern table is ordered by atomic number rather than atomic weight.[2]
3. (c)Germanium was one of the elements Mendeleev left a gap for. State why its eventual discovery strengthened scientists’ confidence in the table.[1]