Atomic structure and the periodic table

Question 1

What is an atom?

Answer 1

The smallest part of an element that can still be recognised as that element

Question 2

What is a compound?

Answer 2

•A substance made when two or more elements are chemically bonded together.
•Can only be separated into elements by chemical reactions

Question 3

What is a mixture?

Answer 3

•When some elements or compounds are mixed together but do not react together
•Impure substance

Question 4

How can mixtures be separated?

Answer 4

Physical process e.g
•Filtration
•Crystalisation
•Fractional distilation
•Chromotograhy
•Simple distillation

Question 5

What is the relative charge of a proton?

Answer 5

+1

Question 6

What is the relative charge of a neutron?

Answer 6

0

Question 7

What is the relative charge of an electron?

Answer 7

-1

Question 8

What is the relative mass of a proton?

Answer 8

1

Question 9

What is the relative mass of a neutron?

Answer 9

1

Question 10

What is the relative mass of an electron?

Answer 10

very small

Question 11

Describe the nucleus of an atom?

Answer 11

*in the middle of the atom
*contains protons and neutrons
*positive charge due to protons
*almost whole mass of atom is concentrated at the atom

Question 12

Describe the electrons of an atom?

Answer 12

•move around in electron shells
•negatively charged
•have virtually no mass

Question 13

Why do atoms have no overall charge?

Answer 13

The number of electrons is equal to the number of protons in the nucleus

Question 14

What is the atomic number of an atom?

Answer 14

the number of protons it contains

Question 15

What is the mass number of an atom?

Answer 15

The bigger number, the sum of the protons and neutrons

Question 16

What is the relative atomic mass of an atom?

Answer 16

An average value that takes into account the abundance of the isotopes of the element.

Question 17

Describe the electronic structure of an atom?

Answer 17

maximum 2 electrons in the first shell
maximum 8 in the second shell
maximum 8 in the third shell

Question 18

What was Daltons theory of the atom?

Answer 18

solid sphere made up of different elements

Question 19

What was JJ Thomspons theory of the atom?

Answer 19

*developed Daltons theory
*plum pudding model
*atoms were positive sphere of charge embedded with electrons

Question 20

What was Rutherford’s theory of the atom?

Answer 20

*disproved Thompson’s theory
*conducted the alpha particle scattering experiments
*fired positively charged alpha particles at sheet of golf
*expected particles to pass straight through
*some were defected more than expected and some were deflected backwards
*concluded tiny charged nucleus at the center with a cloud of negative electrons

Question 21

What was Bohr’s theory of the atom?

Answer 21

*modern nuclear model
*electrons orbit fixed shells
*further experiments by rutherford showed nucleus divided into smaller particles called protons
*James chadwick proposed the idea of neutral particles called protons also in the nucleus

Question 22

How are elements in the periodic table arranged?

Answer 22

*In order of atomic number
*Elements in the same group have the same number of electrons in their outer shell, giving them similar properties

Question 23

Explain the development of the periodic table.

Answer 23

*arranged by atomic weights before discovery of protons
*Mendeleev left gaps for elements he thought had not been discovered
*elements with properties predicted filled the gaps
*knowledge of isoptopes explained why order of atomic weights was not always correct

Question 24

What is an isotope?

Answer 24

Same number of protons but different number of neutrons

Question 25

What is a metal?

Answer 25

An element that reacts to form a positive ion

Question 26

What is a non-metal?

Answer 26

An element that do not form positive ions

Question 27

Where are metals found in the periodic table?

Answer 27

On the left

Question 28

Where are non metals found on the periodic table?

Answer 28

On the right

Question 29

What are some properties of metals?

Answer 29

*Theyre strong but malleable
*Great at conducting heat and electricity
*Have high boiling and melting points

Question 30

What are some properties of non metals?

Answer 30

*More brittle
*Aren’t always solids
*don’t generally conduct electricity
*often have a lower density

Question 31

Describe group 0 elements.

Answer 31

*Called noble gasses
*Unreactive so do not easily form molecules as have stable arrangements of electrons
*Have 8 electrons in outer shell except helium which has 2
*Boiling points increase going down the group

Question 32

Describe group 1 elements.

Answer 32

*Alkali metals
*1 electron in their outer shell
*Reactivity increases going down the group.

Question 33

How do the first 3 elements of group 1 (Lithium, Sodium, Potassium) react with water?

Answer 33

*React vigorously to produce hydrogen gas and metal hydroxides
*The more reactive (lower down the group) more violent reaction is
*Amount of energy given out by reaction increases going down the group.

Question 34

How do the first 3 elements of group 1 (Lithium, Sodium, Potassium) react with Chlorine?

Answer 34

*React vigorously when heated in chlorine gas to form white metal chloride salts
*Reaction more vigorous as you go down the group

Question 35

How do the first 3 elements of group 1 (Lithium, Sodium, Potassium) react with Oxygen?

Answer 35

*React with oxygen to form metal oxide

Question 36

Describe group 7 elements.

Answer 36

*Known as halogens
*Non-metals and consist of molecules made of pairs of atoms
*Form ionic bonds with metals
*Form covalent bonds with non-metals

Question 37

What are the physical properties of transition metals?

Answer 37

•conduct electricity
• shiny when freshly cut
• high melting points
• high densities
• greater strength
• greater hardness

Question 38

What are chemical properties of transition metal?

Answer 38

• react slowly with oxygen and water or not at all
• some react with halogens
• form ions with different charges
• form coloured compounds
• good catalysts