structure and bonding

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  • Created by: Abi14
  • Created on: 28-03-14 19:38
how are compounds formed?
when two elements react together. the atom of the elements join together by sharing electrons or by transferring electrons to achieve a stable electron structures. atoms of the noble gases have stable electronic structures.
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what is it called when non-metalic elements join together?
they join together by electrons and it is called covalent bonding.
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what happens when metalic and non-metalic elements react together?
the produce an ionic compound. the metals lose their electrons to form a postive ion. non-metalic elements gain electrons to form a negative ion. the ions have the stable electronic structure of a noble gas.
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what do oppositely charged ions do?
they attract each other in the ionic compound and this is called ionic bonding.
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what do elements in group 1 of the periodic table have?
one electron in their highest occupied energy level (outer shell).
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what do elements in group 7 of the periodic table have?
seven electron in their highest occupied energy level (outer shell).
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what does the compound sodium chloride have?
the compound sodium chloride has equal number of sodium ions and chloride ions so we write the formula as NaCl. the sodium ions and chloride ions alternate to form a cubic lattice.
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what does ionic compunds hold in a giant structure?
ionic compound holds oppositely charged ions together in a giant structure. the giant structure of ionic compounds is very regular because all of the ions all pack together neatly.
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what do electrostatic forces do?
strong electrostatic forces of attraction act in all directions. each ion in the giant structure or lattice is surrounded by ions with the opposite charge and so is held firmly in place.
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what does the ratio of ions in an ionic structure depend on?
depends on th charges on the ions. for example, calium ions are Ca2+ and chlorine ions are C-, so calcuim chloride contains twice as many chloride ions as calcium ions and its formula is CaCl2.
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how do we show an ionic compound?
we use dots and cross diagrams to represent the atoms and ions invloved in forming ionic bonds. in these diagrams we only show the electrons in the outermost shell of each atom or ion. brackets around it and write the charges of the atom outside.
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what is the charge of an ionic compound?
neutral.
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how do you make the overal charge of an ionic compound neutral?
by balancing charges. e.g. sodium chloride is NaCl (1 Na+ ion for every 1 Cl- ion) but calcium chloride is CaCl2 (1 Ca2+ ion for every 2 Cl- ions)
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what we do of the ion is made up of more than one element?
if we need to mulitple these ions to write a formula we use brackets. the formula of calcium carbonate is CaCO3 nd the formula for calcium hydroxide is Ca(OH)2.
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why do non-metals need to gain electrons?
to gain a stable electronic structure.
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how can you gain a stable electronic structure in a non-metalic bond?
by sharing electrons with other atoms. each shared pair of electrons stringly attracts the two atoms forming a covalent bond. substances that have atoms held together by covalent bonding arer called molecules.
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what do covalent bonds act between?
a covalent bond acts only between two atoms it bonds to each other, and so many covently bonded together substances consist of small molecules.
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when are giant covalent structures fomed?
when some atoms that can form several bonds, like carbon.
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what are macromolecules?
giant covalent structures
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what are atoms in a metalic element like?
all the same size. they form giant structures in which layers of atoms are arranged in regular patterns.
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what is metalic bonding?
when metal atoms pack together the electrons in the highest energy level (outer shell) delocalise and can move freely between atoms. this produces a lattice of positive ions in a 'sea' of moving electrons.
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what do the delocalised electron attract? (metalic bonding)
the positive ions and hold the giant structure together.
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Other cards in this set

Card 2

Front

what is it called when non-metalic elements join together?

Back

they join together by electrons and it is called covalent bonding.

Card 3

Front

what happens when metalic and non-metalic elements react together?

Back

Preview of the front of card 3

Card 4

Front

what do oppositely charged ions do?

Back

Preview of the front of card 4

Card 5

Front

what do elements in group 1 of the periodic table have?

Back

Preview of the front of card 5
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