atoms and molecules

Question 1

atom definition

Answer 1

a smallest possible particle of an element that has the chemical properties of that element

Question 2

neutrons, electrons and protons are all __

Answer 2

sub-atomic particles

Question 3

what particle has a mass of 1/1840

Answer 3

electron

Question 4

what sub-atomic particle has a negative charge

Answer 4

electrons

Question 5

centre of atom is called

Answer 5

nucleus

Question 6

where is mass concentrated in?

Answer 6

the nucleus, with 99.95%

Question 7

atom is mainly made up of

Answer 7

empty space

Question 8

neutrons act like glue to hold the protons together

Answer 8

true

Question 9

electrons orbitting around nucleus at certain electron shells (energy levels) and are attracted to the positively charged atoms. (protons). Why?

Answer 9

the electrostatic force of attraction

Question 10

atomic number

Answer 10

number of protons in one atom of an element

Question 11

mass number (or nucleon number)

Answer 11

number of protons and neutrons in its atom

Question 12

why must the number of protons ALWAYS be equal to the number of electrons?

Answer 12

because all atoms are neutral. (the charges cancel each other out, resulting in atoms with no charge)

Question 13

nuclide notation is

Answer 13

23
11 Na

Question 14

hydrogen has ___

Answer 14

no neutrons

Question 15

what are isotopes

Answer 15

atoms of the same element with different number of neutrons

Question 16

isotopes have the same number of __ and __, therefore they have ___

Answer 16

protons and electrons

same number of electrons, thus they have similar chemical properties

Question 17

isotopes have diff numbers of neutrons, thus ___

Answer 17

different physical properties
(e.g. rate of diffusion, density, boiling point, melting point)

Question 18

relative atomic mass is defined as the

Answer 18

mass of an average atom of the element

Question 19

relative atomic mass equation

Answer 19

sum of (MASS number of isotope x abundance of isotopes) divided by
100

Question 20

why is relative atomic mass sometimes not a whole number?

Answer 20

average value of mass numbers of all the isotopes of a particular element

Question 21

each orbit has

Answer 21

a specific energy level. They are called shells

Question 22

first shell closest to nucleus has __ energy level

Answer 22

lowest

Question 23

maximum number of electrons in a shell

Answer 23

n squared
then times two
2, 8, 8 (first, fill up the fourth shell with eight electrons first, then fill up third)

Question 24

arrangement of electrons in a shell

Answer 24

up, down, right, left
north south, east west

Question 25

what does an electronic structure show

Answer 25

how electrons are arranged in different shells in an atom

Question 26

groups (2.8, 2.8.8, 2.8.8.8) vertical, same number of valence electrons

Answer 26

periods, (2.4, 2.5, 2.6) horizontal, time periods

Question 27

a fully filled outermost shell ____ to an atom

Answer 27

confers stability

Question 28

Outermost shell is called

Answer 28

the valence shell

Question 29

the electrons in the outermost shell are called

Answer 29

valence electrons

Question 30

noble gases are __

Answer 30

unreactive

Question 31

after atoms achieve a stable electronic structure, they form __

Answer 31

ions, have noble gas configurations

Question 32

when an element achieves a fully filled valence shell

Answer 32

they gain stable electronic structure

Question 33

atoms tend to gain, lose or share electrons to obtain eight electrons in their valence shell. What is this called?

Answer 33

achieving the octet rule

Question 34

Atoms of metals tend to __ electrons

Answer 34

lose, because they have extra

Question 35

an atom is called __ after losing electrons

Answer 35

cations, a positive ion (TIP! cations= caution because something has been lost)

Question 36

metals lose electrons to

Answer 36

achieve a stable electronic structure OF THE NEAREST NOBLE GAS

Question 37

a negative ion is called

Answer 37

anion

Question 38

an ion is a particle that has

Answer 38

a net electrical charge

Question 39

a molecule is

Answer 39

formed when 2 or more atoms are chemically combined together

Question 40

a chemical formula

Answer 40

is an expression of the ratio of combining number of atoms or ions

Question 41

cations have a __ charge while anions have a __ charge. Why?

Answer 41

negative positive because for cations, the number of protons are greater than the number of electrons

Question 42

relative formula mass

Answer 42

the mass number of two elements add up