physical science

atom

- The smallest part of a substance that cannot be broken down chemically.

atom Made up of subatomic par:cles namely:

Protons, Neutrons, and Electrons.

ptotons

positively charged paricles.

electron

negatively charged particles.

neutron

neutral charged particles

red

Electrons

green

Neutrons

blue

protons

Democritus (1st to use the word “atom”)

Believed that atoms were indivisible and indestruc:ble.

aristotle

Rejected the theory of atoms

• Believed in the 4 core elements: fire, water, air and earth

cartions

positive

anions

negative

atomic number

- It is the number of protons in an atom.

For a neutral atom,

Atomic number = number of protons = number of electrons

isotopes

- Atoms of the same number of protons but different number of neutrons.

radioactivity

The nucleus decays spontaneously, releasing its surplus of energy, maJer, or both in the form of three types of

Alpha particles

(α-decay)

beta particles

(β-decay)

alpha decay

The nuclear disintegra:on process that emits alpha par:cles (helium ion) is alpha decay.

BETA DECAY (Beta-Minus)

Beta-minus decay is a radioac:ve decay in which the nucleus emits an electron and an an:neutrino, changing the neutron into a proton.

BETA PLUS DECAY (Positron)

, also known as positron emission that occurs when a proton in a nucleus changes into a neutron, This releases a positron and a neutrino, and reduces the atomic number of the element by one.

ELECTRON CAPTURE

Process that unstable atoms can use to become more stable.