Chemistry (Elements, Compounds and Atoms)

Question 1

Element

Answer 1

A pure substance made only from one type of atom - it cannot be broken down into two or more simpler substances by means of a chemical reaction

Question 2

Compound

Answer 2

Substances containing two or more elements that are chemically combined, with the elements in it in a fixed ratio.
The elements in a compound are difficult to seperate and therefore can only do so with a chemical reaction.

Question 3

Mixture

Answer 3

Substances containing two or more elements OR compounds in no fixed ratio and which are not chemically bonded.

Question 4

Atom

Answer 4

The smallest unit of matter that forms an element and cannot be divided. It is made of protons and neutrons (in the nucleus) and electrons (on the rings)

Question 5

Molecule

Answer 5

A group of two or more atoms bonded together.
Molecules can contain atoms of the same type - these are molecules of an element.
Molecules can contain atoms of different type - these are molecules of a compound.

Question 6

Ion

Answer 6

An atom or molecule that has gained or lost one or more of its electrons.
Positively charged ions are called CATIONS (that are PAWSITIVE).
Negatively charged ions are called ANIONS (A Negative ION).

Question 7

Two types of Elements

Answer 7

1) Metal
2) Non-metal

Question 8

Appearance
Metal VS Non-metal

Answer 8

Metals are shiny when polished.
Non-metals are dull when solid.

Question 9

Melting and Boiling Points
Metal VS Non-metal

Answer 9

Metals have high melting and boiling points and are all solid at room temp, except for mercury (a liquid).
Non-metals have low melting and boiling points and are mostly gases at room temp.

Question 10

Malleability
(Definition)

Answer 10

The ability to be hammered into shape

Question 11

Malleability
Metal VS Non-metal

Answer 11

Metals are malleable.
Non-metals are not malleable.

Question 12

Ductility
(Definition)

Answer 12

The ability to be stretched into a wire

Question 13

Ductility
Metal VS Non-metal

Answer 13

Metals are ductile.
Non-metals are not ductile.

Question 14

Electrical Conductivity
Metals VS Non-metals

Answer 14

Metals are good electrical conductors.
Non-metals are poor electrical conductors, except the graphite form of carbon.

Question 15

Thermal Conductivity
Metals VS Non-metals

Answer 15

Metals are good thermal conductors.
Non-metals are poor thermal conductors.

Question 16

Two main parts of the atom

Answer 16

1) Nucleus
2) Electron Cloud

Question 17

Do electrons move?

Answer 17

Yes! They rotate in the shells like the planets in our Solar System.

Question 18

Another word for “Electron Shell”

Answer 18

(Electron) Orbital

Question 19

What does the Atomic Number tell us

Answer 19

The number or protons and electrons as they will always be equal (if it is a pure substance)

Question 20

What does the Mass Number tell us

Answer 20

The number of protons added to the number of neutrons

Question 21

How to find the number of neutrons

Answer 21

Minus the mass number from the atomic number

Question 22

What would you classify protons, neutrons and electrons

Answer 22

Particles

Question 23

Relative charge of protons, neutrons and electrons

Answer 23

P= Positive (+1)
N= Neutral (0)
E= Negative (-1)

Question 24

Relative mass of protons, neutrons and electrons

Answer 24

P= 1
N= 1
E= 1/1836

Question 25

How do the mass and atomic number compare

Answer 25

The mass number will always be bigger than the atomic number

Question 26

What determines what type of atom and element it is

Answer 26

The atomic number, as every element has a different number of protons

Question 27

Main concepts of the Atomic Theory Timeline

Answer 27

1) Discovered particles and atoms 2) Discovered different elements have different atoms 3) Discovered the electron 4) Discovered the proton and the nucleus 5) Discovered the electron shell/orbital 6) Discovered the neutron

Question 28

Main scientists of the Atomic Theory Timeline and Dates

Answer 28

1) 460BC - Democritus 2) 1808 - John Dalton 3) 1897 JJ Thomson 4) 1911 - Ernest Rutherford 5) 1913 - Niels Bohr 6) 1932 - James Chadwick

Question 29

Demorcitus' Theory (The Atomic Theory Timeline)

Answer 29

Discovered particles and atoms - named atoms after Greek work "atomos", meaning "indivisible" or "uncuttable".

Question 30

John Dalton's Theory (The Atomic Theory Timeline)

Answer 30

All atoms are made up of tiny indestructible, indivisible particles. Atoms of one element are all the same. Atoms of one element are different to atoms of a different element. Compounds are made up by combining atoms of different elements in a fixed ratio.

Question 31

JJ Thomson's Theory (The Atomic Theory Timeline)

Answer 31

The cathode rays he discovered were electrons. Electrons has a negative charge (as they were attracted towards a positive charge). All atoms contained electrons. Atoms were made of positive matter with negative electrons scattered throughout like plums in a plum pudding model. He thought there was a general ball of positive charge with negative charged ball floating inside of it.

Question 32

Ernest Rutherford's Theory (The Atomic Theory Timeline)

Answer 32

Discovered the proton and the nucleus. The massive reflection of some alpha particles could only be caused if the positive charge of the atom was concentrated in a nucleus. The fact that most alpha particles passed through with only a small deflection meant that this nucleus was very small. He thought there was a positive nucleus and a cloud of negative charge surrounding it.

Question 33

Niels Bohr's Theory (The Atomic Theory Timeline)

Answer 33

Discovered orbitals. Thought that electrons are found in specific energy levels or "shells"

Question 34

James Chadwick's Theory (The Atomic Theory Timeline)

Answer 34

Discovered neutrons - thought the nucleus of an atom contains protons and NEUTRONS.

Question 35

Names and Concepts of the Atomic Theory Timeline

Answer 35

1) Democritus: Atoms as indivisible particles 2) John Dalton: Billiard Ball Theory 3) JJ Thomson: Plus Pudding Model 4) Ernest Rutherford: The Nuclear model - atoms have a tiny, positive nucleus 5) Niels Bohr: Electrons have energy shells/orbitals 6) James Chadwick: Nucleus contains protons and neutrons

Question 36

Isotopes

Answer 36

Atoms of the same element that have: * The same number of protons * The same number of electrons * Different number of neutrons

Question 37

Relative Atomic Mass (Definition)

Answer 37

SIMPLY: The average mass of an atom. PROPER: The weighted average mass of an atom compared to 1/12th the mass of a 12C atom

Question 38

Relative Atomic Mass (Equation)

Answer 38

Ar = (relative isotopic mass 1 x %) + (relative isotopic mass 2 %) / 100 OR Ar = mass x abundance + mass x abundance / total abundance

Question 39

The amount of electrons that can fit in energy levels

Answer 39

1st shell: 2 electrons 2nd shell: 8 electrons 3rd shell: 8 electrons 4th shell: 8 electrons

Question 40

What is the link between the Group number and the electronic structure?

Answer 40

The group relates to how much/many electrons there are on the outermost shell

Question 41

What is the link between the period number and the electronic structure?

Answer 41

The period relates to the number of sells/orbitals

Question 42

What is the link between the metals and non-metals and electron configuration?

Answer 42

Metals have less tan 4 electrons in the outer shell

Question 43

What group is full of unreactive elements because they all have a full outer shell?

Answer 43

Noble gases - Group 0/Group 8

Question 44

Which group of the periodic table contains the most reactive elements? Why?

Answer 44

Group 1 - empty out shell (apart from one electron). Alkali metals (Group 1) only have one electron in their outer shell. This single electron is easily lost, leading to the formation of positive ions and chemical reactions.

Question 45

What happens to the reactivity of these metals as you go down the group? Why?

Answer 45

More reactive - bigger space (no electrons in it). This is because the outermost electron is further from the nucleus and is less tightly held due to the increased electrons shielding from the inner electrons. Therefore, it is easier for these metals to lose their outer electron and react.

Question 46

Which group of the periodic table contains the most reactive non-metals? Why?

Answer 46

Group 3 - for example, Boron has the most space with no electrons in it. Halogens (Group 3) are highly reactive because they have seven electrons in their outer shell and require only one more electron to react with other elements.

Question 47

What happens to the reactivity of these non-metals as you go down the group? Why?

Answer 47

Less reactive - no space for electrons. This is due to the increased distance of the outer electrons from the nucleus, which results in a weaker attraction for additional electrons. Consequently, larger halogen atoms are less effective at gaining an electron compared to their smaller counterparts.

Question 48

Period

Answer 48

A horizontal row of elements

Question 49

What do you do when writing electron structures?

Answer 49

Use square brackets. For example, the electron configuration for "Cl-" would be [2,8,8]-

Question 50

What particle gets gained and lost?

Answer 50

Electrons

Question 51

How do electrons get gained and lost?

Answer 51

During chemical reactions (specifically gained through reduction and lost through oxidisation). For example metals such as Na (Sodium) can lose one electron to form a positively charged ion (Na+). This is oxidisation - donating electrons to hat they are reacting with. Non-metals, such as Cl (Chlorine) can gain one electron to form a negatively charged ion (Cl-). This is reduction.

Question 52

Why do electrons get gained and lost?

Answer 52

Atoms tend to gain or lose electrons to achieve a full outer shell, following the "octet rule" which states that atoms are most stable when they have eight, or maximum, electrons in their outer shell.

Question 53

Negative ions

Answer 53

Anions: A Negative I O N

Question 54

Positive ions

Answer 54

Cations: Cations are PAWSITIVE