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Chaper 5 science
Section 1,2,3 2012
Question | Answer |
---|---|
Valence electron | Electrons that have the highest energy level and are held very loosely.These are only on the outer shell. |
Ions | An atom with an elelctric charge caused by the loss/gain of valence electrons.2 types of ions: Cations (+)+ Anions (-).Properties: High melting points, electrical conductivity (dissolved in water), made of crystals. Metal+Nonmetal reacting. |
Cation | A positively charged ion. |
Anion | A negatively charged ion. |
Formula to name Ionic bonds | The metal is written first, then the nonmetal. Write the normal name for the metal element. If there is more than one nonmetal, add -ide. If there is one nonmetal, add -ite or -ate. |
Covalent bond | A Chemical bond that involves sharing a pair of electrons between atoms in a molecule. 2 types of Covalent bonds:Polar+Non-polar. 2 nonmetals reacting to each other. Share valence electrons.Properties: bad conductivity,low meling points+boiling points. |
Polar bonds | A covalent bond in which electrons are unequally shared. |
Non- Polar Bonds | A covalent bond where both sides pull equally on electrons. |
Formula to name Covalent bonds | Element furthest left on periodic table first. Add a prefix to the first element only if there is more than one. Add a prefix to hte second element. |
Formula to determine # of shells | The elements in each period have the same number of shells as the period number. (horizontal) |
Formula to determine number of total electrons | Each element has the same number of electrons as their atomic number. |
Formula to determine number of electrons gained or lost | # of electrons gained or lost is determined by how many Valence electrons the element needs to gain or lose to reach 0 or 8. ( 4 goes either way) |
Lewis Dot structure | Lewis dot structures are drawn to show how many valence electrons are in an element. They start at the right and go counter clockwise. |
Subscript | A subscript is the little number beneath/next to the compound and tells you the ratio of elements in the compound. |
Formula to determine number of Valence electrons | Formula to determine number of Valence electrons is the same as the group it's in (Or the second numnber of the group #, ex. 16 is 6) |