Science

• Atoms are made up of smaller particles. These particles are called subatomic particles.
• The three main types of subatomic particle are protons, neutrons and electrons.
• What subatomic particles are found in the nucleus of an atom?
• Protons have a positive charge (positive) and they are very heavy.
• Electrons have a negative charge
• Neutrons have no charge (neutral) and they are also very heavy.
• Democritus, a greek philosopher, proposed that all matter is made up of very small, indivisible particles
• Atomos is the greek word for indivisible
• Democritus theory was referred as atomism
• John Dalton developed the atomic model based on Democritus' ideas
• J J Thomson discovered electrons using cathode ray tubes
• The atomic number is the number of protons in the atom.
• The mass number refers to the total number of protons and neutrons in the atom
• The periodic table is a systematic and organized way of presenting elements.
• The periodic table of elements is classified according to the type of element. Metals, Non metals, and metalloids
• When elements are clustered vertically, they are classified as groups.
• When elements are clustered per row, they are collectively called periods
• Metals are usually found on the left side of the periodic table, except for hydrogen.
• Nonmetals are usually found on the right side of the periodic table.
• Metalloids are found between representative metal and nonmetal elements and are usually recognized in a ladder-like pattern.
• The periodic table of elements is divided into four major groups: the representative elements which are labeled as the A group, the transition elements which are labeled as the B group, and the actinides and lanthanides found at the bottom of the periodic table.