topic1-key concepts in chem

Question 1

what is the electron shell rule

Answer 1

1st shell=2 electrons, 2nd shell=8electrons, 3rd shell=8electons

Question 2

what are ions

Answer 2

charged particles

Question 3

what happens when a shell gains an ion

Answer 3

becomes negative

Question 4

what happens when a shell loses an ion

Answer 4

it becomes positive

Question 5

which groups are most likely to form ions

Answer 5

group 1,2,6,7

Question 6

what structure do ionic compounds have

Answer 6

regular lattice

Question 7

ions form a closely packaged regular lattice which means

Answer 7

they are very strong electrostatic forces of attraction

Question 8

ions have strong attraction which means

Answer 8

they have a high melting and boiling point

Question 9

benefit of 2D representation of structures

Answer 9

simple and great at showing what atoms it contains

Question 10

disadvantage of 2D representation of a structure

Answer 10

don’t show the shape

Question 11

benefit of dot and cross diagram that show a structure

Answer 11

shows how compounds or molecules are formed

Question 12

disadvantage of dot and cross diagram of a structure

Answer 12

don’t show size

Question 13

benefit of 3D model of a structure

Answer 13

show arrangement of ions

Question 14

disadvantage of 3D models that show a structure

Answer 14

only shows the outer layer of a substance

Question 15

benefit of ball and stick models that show a structure

Answer 15

help visualise the structure and are more realistic

Question 16

disadvantage of ball and stick models when showing a structure

Answer 16

don’t show correct scales

Question 17

what are the properties of simple molecular substance

Answer 17

very strong covalent bond but forces of attraction are very weak

Question 18

name properties of a giant covalent bond

Answer 18

very high melting and boiling point

Question 19

describe the diamond structure

Answer 19

it’s a strong and takes lots of energy to break

Question 20

describe the graphite structure

Answer 20

very weak because there aren’t any covalent bonds between layers

Question 21

what’s a general property of metal

Answer 21

strong, lots of energy, high melting and boiling points