bio p table and Chemical quantities

Question 1

What is a compound?

Answer 1

Substance made of more than one type of atom chemically joined together

Question 2

What is a mixture?

Answer 2

two or more substances not chemically combined

Question 3

9 Give the general equations for the reactions of alkali

Answer 3

metals with oxygen, chlorine, and water.
metal + oxygen ➞ metal oxide
metal + chlorine ➞ metal chloride
metal + water ➞ metal hydroxide + hydrogen

Question 4

Why did Mendeleev swap the order of some elements?

Answer 4

to group them by their chemical properties

Question 5

How is the modern Periodic Table ordered?

Answer 5

by atomic number

Question 6

How can you convert a volume reading in cm3 to dm3?

Answer 6

divide by 1000

Question 7

How can you calculate the number of neutrons in an atom?

Answer 7

mass number – atomic number

Question 8

Why does the reactivity of the alkali metals increase down the group

Answer 8

They are larger atoms, so the outermost electron is
further from the nucleus, meaning there are weaker
electrostatic forces of attraction and more shielding
between the nucleus and the outer electron, and it is easier to lose the electron

Question 9

Where are metals and non-metals located on the Periodic Table?

Answer 9

metals to the left, non-metals to the right

Question 10

How do the melting points of the halogens change down the group?

Answer 10

increase (higher melting point)

Question 11

What is a limiting reactant?

Answer 11

The reactant that is completely used up in a
chemical reaction

Question 12

What is a mole?

Answer 12

mass of a substance that contains 6.02×1023 particles

Question 13

How can concentration in mol/dm3 be calculated?

Answer 13

moles of solute/volume (dm3)

Question 14

How does the reactivity of the halogens change down the group?

Answer 14

decrease (less reactive)

Question 15

Why are the noble gases inert?

Answer 15

They have full outer shells, so they do not need to lose or gain electrons

Question 16

What is a unit for concentration?

Answer 16

G/dm3 or mol/dm3

Question 17

Which formula is used to calculate the number of moles from mass and Mr?

Answer 17

Mass = moles × Mr

Question 18

Give the formulae of the first four halogens.

Answer 18

F2 Cl2, Br2 I2

Question 19

How many electrons would you place in the first, second, and third shells?

Answer 19

up to 2 in the first shell and up to 8 in the second and third shells

Question 20

If the amount of solute in a solution is increased, what happens to its concentration?

Answer 20

increases

Question 21

Why did Mendeleev leave gaps in his Periodic Table?

Answer 21

leave room for elements that had not yet been discovered

Question 22

If the volume of water in a solution is increased, what happens to its concentration?

Answer 22

decreases

Question 23

What is the relative charge of each sub-atomic particle?

Answer 23

proton: +1, neutron: 0, electron: −1

Question 24

Why do elements in a group have similar chemical properties?

Answer 24

have the same number of electrons in their outer shell

Question 25

How does the reactivity of the alkali metals change

Answer 25

increases (more reactive)

Question 26

How do the melting points of the noble gases change down the group

Answer 26

increase (higher melting point

Question 27

How can you find out the number of protons in an atom?

Answer 27

The atomic number on the Periodic Table

Question 28

What is an atom?

Answer 28

smallest part of an element that can exist

Question 29

What name is given to the Group 7 elements?

Answer 29

halogens

Question 30

Which formula is used to calculate mass from concentration in g/dm3 and volume?

Answer 30

Mass (g) = concentration (g/dm3) × volume (dm3)

Question 31

What is an element?

Answer 31

Substance made of one type of atom

Question 32

Why do atoms have no overall charge?

Answer 32

equal numbers of positive protons and negative electrons

Question 33

Which formula is used to calculate concentration from mass and volume?

Answer 33

concentration (g/dm3 = mass (g) volume (dm3)

Question 34

Why does the reactivity of the halogens decrease down the group?

Answer 34

They are larger atoms, so the outermost shell is further from the nucleus, meaning there are weaker electrostatic forces of attraction and more shielding between the nucleus and outer shell, and it is harder to gain an electron

Question 35

What is a displacement reaction?

Answer 35

When a more reactive element takes the place of a less reactive one in a compound

Question 36

What are the four physical processes that can be used to separate a mixture?

Answer 36

filtration, crystallisation, distillation, fractional distillation, chromatography

Question 37

What is the relative mass of each sub-atomic particle?

Answer 37

proton: 1, neutron: 1, electron: 0 (tiny)

Question 38

What name is given to the Group 0 elements?

Answer 38

noble gases

Question 39

What are isotopes?

Answer 39

atoms of the same element (same number of protons) with different numbers of neutrons

Question 40

Why are the alkali metals named this?

Answer 40

they are metals that react with water to form an alkali

Question 41

Where are protons and neutrons?

Answer 41

In the nucleus

Question 42

What is relative mass?

Answer 42

The average mass of all the atoms of an element

Question 43

How were the early lists of elements ordered?

Answer 43

by atomic mass

Question 44

What name is given to the Group 1 elements?

Answer 44

Alkali metals

Question 45

Give the value for Avogadro's constant.

Answer 45

6.02×1023