grade 9 chemistry

• An atom is the smallest unit of matter that retains the properties of an element.
• Neutrons do not carry any electrical charge.
• Protons have a positive charge (+1), while electrons have a negative charge (-1).
• The number at the top left is the amount of protons the element has, the two letters is the symbol, the element name is below it, and the numbers underneath the element name is the atomic mass.

  
• The nucleus contains the protons and the neutrons
• electrons are negatively charged particles that move around the nucleus at blinding speed.
• The areas electrons occupy are called shells.
• Neutrons have no charge at all
• Protons have a positive charge
• Protons and neutrons give the element its atomic weight.
• To find how many protons or neutrons are in an element, you must subtract one or the other from the atomic weight.
• An element is defined by the amount of protons it has, meaning if you were to change the number of protons, the element would change as well.
• The classifications of the periodic table are metals, non-metals, and semi-metals.
• Each row of the periodic table is called a period, and each column is called a family
• Ionic charges indicate how many electrons an element gains or loses. (Ex: Aluminium has +3 Ionic charge which means it loses 3 electrons)
• Alkali metals and Alkaline metals are metals found on the far left side of the periodic table. They give atoms (+1 or +2 charge) rather than take.
• Halogens take valence elections and do not give
• Non-metals gain electron(s), while Metals lose electron(s).
• Poor metals are found beneath the staircase, they are there because they all share a lower boiling point and melting point than the others
• Metalloids have properties that fall between those of metals and non-metals.
• Noble gasses are not reactive because they have a stable outer shell
• Covalent bonds form when two elements share electrons
• Mass Number is the sum of the proton and neutron numbers.
• When a metal and non-metal react or collide, there can be a transfer of electrons from one to the other called an ionic compound.
• A shell that contains valence electrons is called a valence shell
• A valence electron are the electrons that are found in the outermost shell of the atoms, the strays as I put it
• To determine the amount of electrons in an element on the periodic table you find the amount of protons and write that, electrons are usually equal with protons unless their valence
• covalent compounds are when two atoms share or conjoin electrons forming molecules.
• Ionic compounds have high melting points and are hard to seperate, conduct eletricity when dissolved in water and is brittle
• Roman numerals tell us the difference between the ionic charges