What is the relative mass and charge of a proton?

Relative mass 1 and relative charge +1.

What is the relative mass and charge of a neutron?

Relative mass 1 and relative charge 0.

What is the relative mass and charge of an electron?

Relative mass very small (about 1/1840) and relative charge -1.

Why is a neutral atom uncharged?

It has the same number of protons (+) as electrons (-), so the charges cancel.

Why does the nucleus contain almost all of an atom's mass?

Protons and neutrons are much heavier than electrons.

Describe Dalton's model of the atom.

Tiny, solid spheres that cannot be divided.

Describe the plum pudding model.

A ball of positive charge with electrons embedded in it (Thomson).

What did Rutherford's experiment show?

Atoms have a small, dense, positive nucleus and are mostly empty space.

What happened to most alpha particles in the gold foil experiment?

They passed straight through, because an atom is mostly empty space.

What did the few bounced-back alpha particles show?

The positive charge is concentrated in a tiny, dense nucleus that repelled them.

What did Bohr add to the atomic model?

Electrons move in fixed shells at set distances from the nucleus.

Subatomic particles and the nuclear atomIB MYP Chemistry: Flashcards

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What are the three subatomic particles?

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What are the three subatomic particles?: Protons, neutrons and electrons.
What is the relative mass and charge of a proton?: Relative mass 1 and relative charge +1.
What is the relative mass and charge of a neutron?: Relative mass 1 and relative charge 0.
What is the relative mass and charge of an electron?: Relative mass very small (about 1/1840) and relative charge -1.
Where are protons and neutrons found?: In the nucleus.
Where are electrons found?: In shells around the nucleus.
Why is a neutral atom uncharged?: It has the same number of protons (+) as electrons (-), so the charges cancel.
Why does the nucleus contain almost all of an atom's mass?: Protons and neutrons are much heavier than electrons.
Describe Dalton's model of the atom.: Tiny, solid spheres that cannot be divided.
Describe the plum pudding model.: A ball of positive charge with electrons embedded in it (Thomson).
What did Rutherford's experiment show?: Atoms have a small, dense, positive nucleus and are mostly empty space.
What happened to most alpha particles in the gold foil experiment?: They passed straight through, because an atom is mostly empty space.
What did the few bounced-back alpha particles show?: The positive charge is concentrated in a tiny, dense nucleus that repelled them.
What did Bohr add to the atomic model?: Electrons move in fixed shells at set distances from the nucleus.

Exam questions on Subatomic particles and the nuclear atom

A school technician is making a poster about the particles inside a carbon atom. The poster must show students the three types of subatomic particle, where each one is found in the atom, and how their masses and charges compare.
Describe the relative mass and relative charge of a proton and of an electron.2 marks
In 1911 a team of scientists fired a beam of positively charged alpha particles at a very thin sheet of gold foil and used a detector to record where the particles ended up. Before this, many scientists pictured the atom as a ball of positive charge with tiny electrons scattered through it. The team found that nearly all the alpha particles passed straight through the foil, a small number were deflected through large angles, and a very few bounced almost straight back.
Explain why most alpha particles passed straight through the foil but a very few bounced back.2 marks
A science teacher is preparing a lesson on a lithium atom, which contains 3 protons, 4 neutrons and 3 electrons. She also wants to show how scientists' ideas about the atom changed between the early 1800s and the early 1900s. Students may use the fact that protons and neutrons have a relative mass of 1 and that an electron has a negligible relative mass.
Explain why a lithium atom has no overall charge and why almost all of its mass is in the nucleus.3 marks

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Written by the Exaim team, led by Shaun Daswani (Head of Upper Secondary, Improve ME Institute; MSc Financial Mathematics, Imperial College London; BSc, UCL) and Jason Daswani (operational lead, Improve ME Institute; LSE).