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What is the smallest part of an element that can exist?
an atom
What is an element?
A substance made up of only one type of atom
What is a compound?
A substance made up of two or more different types of atom that are chemically bonded together
What is a mixture?
A substance made up of two or more elements or compounds that are not chemically bonded together
What is a molecule?
A substance made up of two or more atoms that are chemically bonded together
How would you separate an insoluble solid from a liquid?
Filtration
How would you separate two liquids?
Distillation
How would you separate a mixture of coloured compounds?
Chromatography
What is the plum pudding model of the atom?
the atom is a ball of positive charge with negative electrons embedded in it
What is the nuclear model of the atom?
the atom contains a charged nucleus in the centre which contains most of the mass of the atom
What conclusions were drawn from the alpha particle scattering experiment?
The mass of an atom is concentrated in the nucleus and the nucleus is charged
Who adapted the nuclear model to included electron shells?
Niels Bohr
What was Niels Bohr's contribution to the atomic model? (2)
He suggested that electrons orbit the nucleus at specific distances
His theoretical calculations agreed with experimental observations
Who provided the evidence to show neutrons existed?
James Chadwick
What was James Chadwick's contribution to the atomic model? (2)
He provided the evidence to show the existence of neutrons within the nucleus
This was about 20 years after the nucleus became an accepted scientific idea
What is the relative charge of an electron?
-1
What is the relative charge of a neutron?
0
What is the relative charge of a proton?
1
What is the charge of the nucleus of an atom?
Positive
What is the charge of an atom?
Neutral
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 (close to 0)
Where in atoms are protons found?
nucleus
Where in atoms are neutrons found?
nucleus
Where in atoms are electrons found?
Electron shells
What does the mass number of an atom represent?
The number of protons and neutrons in the nucleus of an atom
What does the atomic number of an atom represent?
The number of protons in the nucleus of an atom
How can you work out the number of electrons in an atom?
It will be the same as the number of protons
How can you work out the number of protons in an atom?
It is the atomic number
How can you work out the number of neutrons in an atom?
mass number - atomic number
What is relative atomic mass?
The average mass of all the atoms of an element
How many electrons does the first electron shell hold?
2
How many electrons does the second electron shell hold?
8
How many electrons does the third electron shell hold?
8
How are elements arranged in the periodic table?
By increasing atomic (proton) number
What are the rows in a periodic table called?
periods
What are the columns in a periodic table called?
groups
What does the group number tell you about elements?
the number of electrons in the outer shell
What do elements in the same group have in common?
they have similar properities
Why do elements in the same group have similar chemical properties?
they have the same number of electrons in their outer shell (outer electrons)
Who developed the modern periodic table?
Mendeleev
Why did Mendeleev leave gaps in his periodic table?
For undiscovered elements
How did Mendeleev arrange the periodic table?
in order of increasing atomic weight - however, he changed the order for some elements based on their properties
Where are metals found on the periodic table?
To the left hand side
Where are non metals found on the periodic table?
To the right hand side
What charge do metal ions have?
Positive
What charge do non metal ions have?
Negative
How do metals form ions?
lose electrons
How do non metals form ions?
They gain electrons to form negatively charged ions
What is the name of the elements in group 0?
noble gases
Why are group 0 elements unreactive?
their atoms have stable arrangements of atoms (full outer shells)
How does the boiling point of group 0 elements change as you go down the group?
Boiling point increases
What is the name of the metals in group 1?
alkali metals
How many electrons do group 1 metals have in their outer shell?
one
Why do group 1 metals have similar characteristic properties?
they all have one electron in their outer shell
How does the reactivity of group 1 metals change as you go down the group?
They get more reactive
What is the name of the elements in group 7?
halogens
How many electrons do group 7 elements have in their outer shell?
7
Why do group 7 elements have similar characteristic properties?
they all have seven electrons in their outer shell
How does the mass of group 7 elements change as you go down the group?
mass increases
How does the melting and boiling point of group 7 elements change as you go down the group?
increase
How does the reactivity of group 7 elements change as you go down the group?
less reactive
What is a displacement reaction?
A reaction in which a more reactive element takes the place of a less reactive element in a compound
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