covalent bonding Flashcards

1
Q

when atoms share pairs of electrons what do they form?

A

covalent bonds

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2
Q

what is the definition of covalent bonding?

A

the strong electrostatic attraction between a shared pair of electrons and the protons in the nuclei

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3
Q

why do simple covalent bonds not conduct electricity?

A

they dont contain free electrons

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4
Q

why do simple molecular substances have a low melting and boiling point?

A

only weak intermolecular forces acting between the molecules

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5
Q

the intermolecular forces are usually what compared to the covalent bonds?

A

weak

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6
Q

most simple molecules are what at room temperature?

A

liquid or gas

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7
Q

as the molecules increase in size what happens to the intermolecular forces?

A

they also increase

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8
Q

the intermolecular forces increasing in size means what?

A

the melting and boiling points increase

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9
Q

are covalent structures good or bad conductors of energy?

A

bad as there are no free ions or electrons to carry the charge

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10
Q

the simple molecules contain what number of atoms?

A

fixed

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11
Q

giant covalent structures contain what number of atoms?

A

a huge number( a giant lattice)

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12
Q

diamond and graphite are what of carbon?

A

allotropes

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13
Q

in diamond, each carbon atoms forms with how many other carbon atoms?

A

4- forming a tetrahedron

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14
Q

what are the covalent bonds like in diamond?

A

identical, very strong and there are no intermolecular forces

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15
Q

what are diamonds physical properties?

A

very hard, has a very high melting point and it doesnt conduct electricity

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16
Q

does diamond have any freely charged particles?

A

no-therefore it cannot conduct electricity

17
Q

what is a large amount of heat required to break?

A

the lattice

18
Q

what are the atoms arrangements in silicon dioxide?

A

each oxygen atom forms covalent bonds with 2 silicon atoms and each silicon atom forms covalent bonds with 4 oxygen atoms

19
Q

what is the tetrahedron in silicon dioxide formed by?

A

one silicon atom and 4 oxygen atoms

20
Q

does silicon dioxide have covalent bonds?

A

yes lots of very strong covalent bonds

21
Q

does silicon dioxide have intermolecular forces?

A

no

22
Q

physical properties of silicon dioxide?

A

very high boiling point, insoluble in water and doesnt conduct electricity

23
Q

why is silicon dioxide cheap and what is it used for?

A

its available naturally and is used to line furnaces

24
Q

each carbon atom in graphite is covalently bonded to how many other carbon atoms?

A

3 others-forming layers of hexagons leaving one free electron per carbon atom

25
Q

how can graphite conduct electricity?

A

these free electrons migrate along the layers and are free to move and carry charge

26
Q

what are the covalent bonds like in graphite?

A

very strong

27
Q

how are the layers of ions in graphite attracted to eachother?

A

by weak intermolecular forces

28
Q

what makes graphite soft and slippery?

A

the layers can slide over eachother as they are attracted by weak intermolecular forces

29
Q

the physical properties of graphite?

A

it can conduct electricity and heat, has a high melting and boiling point and it is soft and slippery and less dense than diamond

30
Q

what makes graphite a useful material?

A

the weak intermolecular forces-make if soft and slippery

31
Q

does fullerene have a large surface area of small surface area?

A

large surface area

32
Q

what happens when non-metal atoms share pairs of electrons?

A

they get a full outer shell

33
Q

what are simple molecules?

A

a small group of atoms held together by covalent bonds

34
Q

when simple molecules boil what breaks?

A

the weak intermolecular forces

35
Q

what does electrical conductivity require?

A

charged particles that can move freely

36
Q

why do simple molecular substances never conduct electricity?

A

because the molecules are neutral

37
Q

c60 fullerene is an electrical…

A

insulator