Chemistry - S1.2 (the nuclear atom)

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relative mass and charge of subatomic particles (table)

Subatomic particles

• protons, neutrons and electrons

• so small that it is not practical to measure their masses and charges using conventional units (relative atomic masses’ and ‘relative atomic charges are used instead) Located in the nucleus.

• nucleus dense because mass of atom is concentrated in nucleus, which contains heaviest subatomic particles.

• subatomic particles in nucleus can be called nucleons (neutrons and protons)

• The electrostatic attraction between the positive nucleus and negatively charged electrons orbiting around it is what holds an atom together

Isotopes

• Isotopes = different atoms of same element that contain same number of protons + electrons but different number of neutrons

  • atoms of same elements but with different mass numbers

Isotopes of hydrogen