2.1: ATOMIC STRUCTURE AND ISOTOPES

What does an atom consist of

1. A nuclueus made up of 2 types of subatomic particles - protons and neutrons

2. Electrons arranged around the nucleus is shells

Charge of subatomic particles

P - 1+

N - 0

E - 1-

Relative masses of subatomic particles

P - 1

N - 1

E - 1/1836

Why are all atoms neutral

equal number of protons and electrons

P = 1+, E = 1- so charges cancel out

Why are neutrons important

They hold the nucleus together despite the electrostatic repulsion between its positively charged protons

What are isotopes

Atoms of the same element with different numbers of neutrons and different masses but the same number of protons and electrons

Why are the chemical reactions of isotopes the same

1. Chemical reactions involve the electrons surrounding the nucleus

2. Diff isotopes of the same element have the same number of electrons

3. The number of neutrons has no effect on reactions of an element

Small differences in physical properties of isotopes

Higher-mass isotopes have:

1. higher mp

2. higher bp

3. higher density

What is an ion

A charged atom

Ions and atoms of an element

Have the same number of protons but a different number of electrons