chemistry

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  • Created by: siobhan5
  • Created on: 08-03-15 13:40
what is a compound?
a substance made of two or more elements that have reacted together or that are chemically bonded together.
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which electrons in an atom are involved in bonding?
outer electrons.
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what happens to the electrons in atoms when ionic bonds are formed?
they are transferred or metal atoms lose electrons and non-metal atoms gain electrons.
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what happens to the electrons in atoms when covalent bonds are formed?
they are shared. for each covalent bond one pair of electrons is shared.
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why do the elements in group 1 form ions with a single positive charge?
they lose their 1 outer electron.
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why do the elements in group 7 form ions with a single negative charge?
they gain one electron so their outer shell has 8 electrons or so they have the structure of a noble gas
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which of the following substances are made of molecules? KCI, H2O, C2H6, MgO, CO2, NaNO3.
H2O, C2H6, CO2
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why can the structure of a metallic element like copper be represented by lots of small spheres the same size packed together?
the atoms in copper are all the same size, they are spherical, they are closely packed together (in a giant structure)
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write the correct formula for each of the following: lithium chloride, sodium oxide, calcium fluoride, magnesium hydroxide, sodium sulphate, calcium nitrate.
LiCI, Na2O, CaF, Mg(OH)2, Na2SO4, Ca(NO3)2
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why do ionic compounds have giant structures?
the attractive forces between oppositely charged ions act in all directions, so the ions pack closely together in a regular arrangement (lattice), ions are very small so crystal contains many ions.
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explain why silicon (in group 4) has a giant structure.
silicon atoms form four covalent bonds, each silicon atom can join to four others, the bonds are strong; this continues so that a giant structure is formed.
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explain how the atoms in a piece of sodium metal are held together.
the outer electrons de-localise, leaving a lattice of positive ions; the de-localised electrons attract the positive ions; the electrostatic forces are strong, and these hold the ions in position.
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Other cards in this set

Card 2

Front

which electrons in an atom are involved in bonding?

Back

outer electrons.

Card 3

Front

what happens to the electrons in atoms when ionic bonds are formed?

Back

Preview of the front of card 3

Card 4

Front

what happens to the electrons in atoms when covalent bonds are formed?

Back

Preview of the front of card 4

Card 5

Front

why do the elements in group 1 form ions with a single positive charge?

Back

Preview of the front of card 5
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