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Chemistry St Peters1
Development of the Periodic Table Key Words
Question | Answer |
---|---|
atomic weights | These are the masses of one atom of an element. Also called relative atomic masses, the early periodic tables were based on atomic weights. |
octaves | Groups of eight. Newlands 'law of octaves' groups of 8 elements where every eight element had similar properties. |
periodic table | The table we use to order the elements based on their atomic masses and their properties. |
atomic number | The number of protons an element has in the nucleus of its atom. |
highest occupied energy level/outer shell | The furthest orbit or energy level from the nucleus containing electrons. |
alkali metals | Metals in Group 1 which form alkalis or alkaline solutions when they react with water. |
ionic compounds | Compounds formed where the atoms involved in the reaction form ions of a - or + charge. Electrons are exchanged by the atoms. |
halogens | The elements in Group 7. They are all non-metals. They have 7 electrons in their outer orbit and form diatomic molecules. They can react to form covalent or ionic bonds. |
molecules | 2 or more atoms chemically bonded together. |
ionic | Ionic bonds create ions (charged atoms). Electrons are exchanged by the atoms in the reaction to give each atom 8 electrons in their highest energy level. |
covalent | Bonds where atoms share electrons |
transition elements | Elements found in the periodic table between Groups 2 and 3. They are all metals. |
catalyst | Something that changes the rate of a reaction without being consumed (used up) in the reaction. |
alloy | A mixture of metals and other elements (often carbon) |