Chemistry

Chemistry

Introduction

• Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter.
• Matter is a physical substance in general, as distinct from mind and spirit; (in physics) that which occupies space and possesses rest mass, especially as distinct from energy.

Key Words

• Elements are simple pure substances.
• Atoms are the smallest function portions of an element.
• Protons in the nucleus define the physical and chemical properties of the elements. Protons determine the characteristics that an element has. If you change the number of protons you change the element.
• Atomic Number-Number of protons in the nucleus. In a neutral atom, the number of protons and electrons should be equal. Therefor the atomic number can tell you the number of protons and electrons.
• Mass Number-The mass number tells us the number of protons plus the number of electrons.

How?

• Uncharged. ''Normal'' atoms have the same number of protons, electrons, and close to the same number of neutrons.
• For Example;
• Protons=13
• Neutrons=14 AL= Aluminium
• Electrons=13