Elements, compounds and mixtures

Question 1

What are atoms?

Answer 1

very tiny particles

Question 2

How many types of atom?

Answer 2

92 that occur naturally

Question 3

What are the two main parts of an atom?

Answer 3

The nucleus and the electron cloud region

Question 4

What types of particle does the nucleus contain?

Answer 4

protons and neutrons

Question 5

What three fundamental particles are atoms of all elements made up of?

Answer 5

protons, neutrons, electrons

Question 6

What is a protons’ relative mass and relative charge?

Answer 6

relative mass: 1

relative charge: +1

Question 7

What is a neutrons’ relative mass and relative charge?

Answer 7

relative mass: 1

relative charge: 0

Question 8

What is a electrons’ relative mass and relative charge?

Answer 8

relative mass: almost 0 (1/2000)

relative charge: -1

Question 9

What are molecules?

Answer 9

The atoms of some elements join together in molecules. Molecules are made up of two or more atoms. Molecules can be formed by two atoms of the same element or by atoms of two different elements.

Question 10

Name some elements that form molecules.

Answer 10

oxygen, hydrogen, nitrogen, chlorine, bromine…

Question 11

What is the atomic number?

Answer 11

The atomic number is the number of protons an atom has (always the smaller number)

Question 12

What is the mass number?

Answer 12

sum of protons and neutrons

Question 13

How do you calculate the electrons?

Answer 13

The same as the protons and therefore atomic number

Question 14

How do you calculate the protons?

Answer 14

The same amount as electrons and atomic number.

Question 15

How do you calculate the neutrons?

Answer 15

mass number - protons

Question 16

If chlorine’s atomic number is 17 and its mass number is 35, what is its number of protons, neutrons and electrons?

Answer 16

protons = 17
neutrons = 18
electrons = 17

Question 17

What are isotypes?

Answer 17

Isotypes are atoms of the same element with the same number of protons but with a different number of neutrons.

Question 18

What is the electronic structure of an atom?

Answer 18

Electrons in atoms are arranged in energy levels (shells)

Energy levels fill from the inside. Only when one level is full will the electrons start going into the next level.

Question 19

How many electrons can each energy level hold?

Answer 19

2,8,8

Question 20

What is the test for hydrogen?

Answer 20

the pop test: lit splint, in the neck of the tube makes a squeaky pop when hydrogen is present

Question 21

Similarity between Magnesium + Hydrochloric acid and Calcium + Hydrochloric acid

Answer 21

Both exothermic: very reactive

Question 22

magnesium + hydrochloric acid =

Answer 22

magnesium chloride + hydrogen

Question 23

calcium + hydrochloric acid =

Answer 23

calcium chloride + hydrogen

Question 24

is the product of calcium + water acid or alkali?

Answer 24

alkali because of alkali earth metals

Question 25

calcium + water =

Answer 25

calcium hydroxide + hydrogen

Question 26

is magnesium or calcium more reactive?

Answer 26

calcium

Question 27

Explain which would be the most reactive metal in period II.

Answer 27

radium as the elements become more reactive as you go down the group because the atomic number goes up

Question 28

describe an atom

Answer 28

atoms consist of a central nucleus containing protons and neutrons. The nucleus is small compared to the size of the whole atom. The nucleus is surrounded by electrons in energy levels, also called shells. Atoms have no electric charge because they contain the same number of protons and electrons. The electrons are arranged in energy levels (shells).

Question 29

How are the atoms in an element arranged?

Answer 29

Elements are made up of only one type of atom. | These atoms can exist as individual atoms (e.g. Ne) or bonded together atoms to form molecules (e.g. O2)

Question 30

How are the atoms in a compound arranged?

Answer 30

Compounds contain atoms of two or more elements and are chemically bonded together. The elements in a compound are difficult to separate and need to undergo chemical change if this is to happen.

Question 31

How are the atoms in a mixture arranged?

Answer 31

The different particles in a mixture are not chemically bonded together and can therefore be separated from each other with relative ease.

Question 32

What is an element?

Answer 32

An element is a substance made from only one type of atom. It cannot be broken down into two or more simple substances by means of a chemical reaction Cannot be broken down into anything simpler.

Question 33

What is a compound?

Answer 33

These substances contain two or more elements that are chemically combined. The elements in a compound are in a fixed ratio which is shown by the formula, e.g. in the compound, water (formula: H2O) there are 2 toms of hydrogen and 1 atom of oxygen.

Question 34

What is a mixture?

Answer 34

These substances contain two or more elements or compounds in a variable ratio and which are not chemically combined.