Studied by 10 people
What are all substances made from?
atoms
What is the smallest part of an element that can exist?
an atom
Approximately how many different elements are there?
100
Where are all of the elements shown?
The Periodic Table
What are formed from elements by chemical reactions?
compounds
What do chemical reactions always involve?
The formation of new substances
What is this the definition of: Substances containing two or more elements chemically combined in fixed proportions
compound
What is this the definition for: Something consisting of two or more elements or compounds not chemically combined together.
mixture
Which processes can be used to separate mixtures?
Filtration, Crystallisation, Distillation, Chromatography, Fractional Distillation
Before the discovery of electrons what were atoms thought to be?
Tiny spheres that could not be divided
Which model was created due to the discovery of the electron?
The Plum-Pudding model
What does the plum pudding model suggest about the atom?
That it is a ball of positive charge with negative electrons embedded in it
What did the results from the alpha particle scattering experiment show?
That the mass of an atom was concentrated at the centre (nucleus) and the nucleus was charged
How did Niels Bohr adapt the nuclear model
He suggested that electrons orbit the nucleus at specific distances
What is the name given to small positively charged particles in the nucleus?
protons
What did the experimental work of James Chadwick provided the evidence for?
neutrons
What is the relative charge of the proton?
+1
What is the relative charge of a neutron
0
What is the relative charge of an electron
-1
In an atom the number of electrons is equal to the number of
protons
What is the atomic number of an element?
the number of protons
All atoms of a particular element have the same number of?
protons
Atoms of different elements have different numbers of
protons
What is the radius of an atom?
0.1nm (1x10-^10m)
How many times smaller is the radius of the nucleus compared to the atom
10,000
What is the relative mass of a proton?
1
What is the relative mass of a neutron?
1
What is the relative mass of an electron?
Very small (1/2000)
What is the mass number of an atom?
the sum of protons and neutrons
What do we call atoms of the same element with different numbers of neutrons
isotopes
Isotopes of an element have a different number of?
neutrons
What is the relative atomic mass of an element?
The average values of the abundance of the isotopes of the element
What is the maximum number of electrons that can be found on the lowest energy level?
2
What is the maximum number of electrons that can be found on the second energy level?
8
How are the elements in the periodic table arranged?
In order of atomic number
What do we call a column in the periodic table?
groups
What do we call rows in the periodic table?
periods
What do elements in the same group in the periodic table have in common?
The same number of electrons in their outer shell
Before the discovery of protons, neutrons and electrons how did scientists classify the elements?
Arranging them in order of their atomic weights
How did Mendeleev overcome problems with creating a periodic table?
By leaving gaps for undiscovered elements
Elements that react to form positive ions are
metals
Elements that do not form positive ions are
non-metals
The majority of elements are
metals
Where are metals found on the periodic table?
To the left and bottom
Where are non-metals found on the periodic table?
To the right and top
What do we call the elements in Group 0?
The noble gases
Why are Group 0 elements unreactive and do not easily form molecules?
They have stable arrangements of electrons
How many electrons do the noble gases have in their outer shell (excluding Helium)
8
What happens to the boiling point of the noble gases as you go down the group?
It increases
Which noble gas has 2 electrons in the outer shell?
Helium
What are the elements in Group 1 know as?
The alkali metals
How many electrons are there in the outer shell of the alkali metals?
1
How does the reactivity of the elements in Group 1 change as you go down the group?
It increases
What is the general equation for the reaction of an alkali metal with chlorine?
Alkali metal + Chlorine → Metal chloride
What is the general equation for the reaction of an alkali metal with water?
Alkali metal + Water → Metal hydroxide + Hydrogen
What is the general equation for the reaction of an alkali metal with oxygen?
Alkali metal + Oxygen → Metal oxide
What are the elements in group 7 known as?
the Halogens
How many electrons do the Group 7 elements have in their outer shell?
7
How are the halogens found?
In pairs of atoms
As you go down Group 7 what happens to the boiling points of the elements?
It increases
As you go down Group 7 what happens to the relative molecular mass of the elements?
It increases
As you go down Group 7 what happens to the reactivity of the elements?
It decreases
What will a more reactive halogen do to a less reactive halogen when in an aqueous solution of its salt?
Displace it
What transition element is used in the Harber process?
Iron
What transition element increases the decomposition of hydrogen peroxide to oxygen and water?
Manganese (IV) oxide
What can the transition elements form?
Coloured compounds Ions with different charges
What colour does Iron(II) hydroxide, Fe(OH)2
Pale green
What colour does Iron(III) hydroxide, Fe(OH)3
Orange- brown
What colour does Iron(III) oxide, Fe2O3
Red-brown
What can the transition elements be used as?
Catalysts
What are the transition elements?
Metals
What are the main transition elements?
Chromium, Manganese, Cobalt, Nickle, Copper
How should the transition elements be simplified as?
Cr, Mn, Fe, Co, Ni, Cu
What do the transition elements have in common?
They have similar properties
How do the transition elements differ from Group 1 metals?
-higher melting points
higher densities -Stronger and harder -Reactivity with oxygen, water and halogen Conducts electricity
What type of bonding occurs between oppositely charged ions?
ionic bonding
What type of bonding occurs between atoms which share pairs of electrons?
covalent bonding
Which type of bonding is found in atoms which share delocalised electrons?
Metallic bonding
Which type of bonding occurs in compounds formed from metals combined with non-metals?
Ionic bonding
Which type of bonding occurs in most non- metallic elements?
Covalent bonding
Which type of bonding occurs in compounds of non-metals?
Covalent bonding
Which type of bonding occurs in alloys?
Metallic bonding
What is transferred in ionic bonding?
electrons
When a metal atom becomes positively charged what has it lost?
electrons
What would be the charge of an ion formed from a Group 1 element?
+1
What would be the charge of an ion formed from a Group 2 element?
+2
What would be the charge of an ion formed from a Group 6 element?
-2
What would be the charge of an ion formed from a Group 7 element?
-1
What is an ionic compound?
a giant structure of ions
What holds ionic compounds together?
Strong electrostatic forces of attraction between oppositely charged ions
Name 2 covalently bonded substances with giant covalent structures
Diamond, Silicon dioxide
Some covalently bonded substances have very large molecules, such as
polymers
How are the atoms arranged in metals?
In a regular pattern
What are the electrons in the outer shell of metal atoms like?
Delocalised
What does delocalised electrons mean?
Electrons that are free to move around
What are the three states of matter?
solid, liquid, gas
What takes place at the melting point?
melting and freezing
What takes place at the boiling point?
Boiling and condensing
How does the strength of the forces between particles affect the boiling point?
The stronger the forces between the particles the higher the boiling point
What are the limitations of the particle model?
There are no forces
All particles are represented as spheres
The spheres are solid
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