Sec 1 Science Atoms & Molecules topical questions

State the charge of a proton, a neutron and an electron, and where each is found.

Explain why a whole atom is electrically neutral.

State the number of each type of atom in one molecule of CO₂.

State what a molecule is.

What is the same in every atom of oxygen?

Compare an atom and a molecule, using O and O₂ as examples.

A neutral atom has 6 protons and 6 neutrons.

1. (a)State the number of electrons.[1]
2. (b)State the reason for your answer.[1]
3. (c)State which number identifies the element.[1]
4. (d)Where is most of the mass?[1]

Read the formula NH₃. State the number of nitrogen atoms and hydrogen atoms, and whether the molecule is an element or a compound.

Explain why O₂ is a molecule of an element, while CO₂ is a molecule of a compound.

Put these in order of size, smallest first: a grain of sand, an atom, a typical cell. Explain why a model is used for the smallest one.

A student says, “The nucleus is negative because that is where the electrons are.” Rewrite the model correctly.

Two atoms each have 17 protons. One has 18 neutrons and the other has 20 neutrons. Are they the same element? Explain.

A formula is written H₂O. A student counts 2 oxygen atoms because “the 2 is in the formula”. Explain the mistake and give the correct count.

Knowledge of atoms has been used both in hospitals and in weapons. Explain why this is an ethical issue, not only a science fact.

Explain how the atomic model and the particle model of solids, liquids and gases fit together, and state one thing the atomic model adds.