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Chapter 2: Atoms, Ions and Compounds.

Atomic Structure and Isotopes:

An isotope is an atom of the same element with a different number of neutrons.

Atomic number is the number of protons in an atoms nucleus, i.e. proton number.

Mass number is the number of particles in the nucleus (nucleon number).

An ion is a positively or negatively charged atom or group of atoms.

The nucleus is made up of protons and neutrons, it has an overall positive charge.

The Ancient Greeks believed everything was made up of very small particles. IN 1808, Dalton did experiments and proved it correct, naming them atoms.

Proton - 1.672x10^27kg, +1.602x10^-19 charge. Relative- 1mass, 1 charge

Neutron - 1.674x10^-27kg, 0 charge. Relative- 1mass, 0 charge

Electron - 9.109x10^-31kg, -1.602x10^-19 charge. Relative- 1/2000 mass, -1charge.

On a periodic table, the highest value is always the mass number and the lowest is the proton number.

Isotopes are atoms of the same element, with different masses but the same numner of protons and electrons (same reactivity).

Relative abundance is the percentage of each isotope that naturally occurs on Earth.

Isotopes are important as they have the same chemical properties but different physical properties.

Ions are formed by gaining or removing electrons. Electrons are negative so less electrons has a greater positive charge overall.

Relative Mass: