Chemistry GCSE Paper 1 Flashcards
How many different elements are in the periodic table?
100
What is a compound?
made from 2 or more elements which are combined chemically
What is a molecule?
formed when two atoms join together by chemical bonds
How can compounds be seperated into elements?
Chemical reactions
What is a mixture?
consists of two or more elements not chemically combined together
What is an atom?
The smallest particle
What is an Element?
made of only one type of atom
What are some examples of physical processes where mixtures can be separated?
Filtration crystallisation simple distillation fractional distillation chromotography
What does chromatography separate?
mixtures which include inks, dyes and colouring agents in food
What does filtration separate?
Separates a solid that can dissolve from one that can’t
What does evaporation separate?
separates a liquid and solid by boiling off the liquid
What does distillation separate?
Separates liquids with different boiling points
What does the plum pudding model suggest?
The atom is a ball of positive charge with negative electrons embedded in it
What did the alpha particle scattering experiment lead to?
led to the conclusion that the mass of an atom was concentrated at the centre and that the nucleus was charged. This nuclear model replaced the plum pudding model
What did James Chadwick experimental work suggest?
provided the evidence to show the existence of neutrons within the nucleus. This was about 20 years after the nucleus became and accepted scientific idea
Who adapted the nuclear model and what did it suggest?
Niels Bohr suggests that electrons orbit the nucleus at specific distances
What did later experiments lead to?
led to the idea that the positive charge of any nucleus could be subdivided into a whole number of smaller particles, each particle having the same amount of positive charge. The name proton was given to these particles
What is the relative charge of a proton?
+1
What is the relative charge of the neutron?
0
What is the relative charge of the Electron?
-1
The number of electrons is equal to the number of what in the nucleus?
protons
What is the atomic number?
number of protons
What is the relative mass of protons?
1
What is the relative mass of neutrons?
1
What is the relative mass of electrons?
very small
What is the mass number?
sum of the protons and neutrons in an atom
What is an isotope?
element that has the same number of protons but a different number of neutrons
What are the elements in the periodic table ordered in?
ordered in atomic number
What are the columns in the periodic table known as?
Groups
Why is the table called the periodic table?
similar properties occur at regular intervals
Elements in the same group in the periodic table have the same number of what?
same number of electrons in their outer shell
How did people attempt to classify elements before the discovery of neutrons protons and electrons?
Arranging them in order of their atomic weight
What are the elements in Group 1 called?
Alkali metals
What does lithium do when it reacts with water?
floats, moves very quickly and fizzes
What does potassium do when it reacts with water?
floats, moves quickly, melts and fizzes gas may ignite with an orange flame
What does sodium do when it reacts with water?
floats, moves slowly and fizzes
Alkali metals generally become …………………. dense going down the group
less
What does caesium do when it reacts with water?
explodes almost instantly and breaks the glass container
How does lithium react when burnt?
orange flame
red flame
burnt fast
white solid left
How does sodium react when burnt?
orange flame
burnt slowly
melted
went silver
How does potassium react when burnt?
purple flame
burnt really fast
melted
Is the lithium oxide alkaline or acid?
Alkaline
Is the sodium oxide alkaline or acid?
Alkaline
Is the potassium oxide alkaline or acid?
Alkaline
Elements that react to form positive ions are …
metals
Elements that do not form positive ions are ….
non - metals
Majority of elements are …
metals
Where are metals found on the periodic table?
left and towards the bottom of the periodic table
Where are non metals found on the periodic table?
towards the right and top of the periodic table
What are the elements in group 0 called?
noble gases
Why are noble gases used for lights?
they don’t mix and are unreactive. They are also less dangerous then other gases
Why are noble gases unreactive?
have a dull outer shell of electrons
Do the atoms get smaller or bigger further down the group 0?
bigger
Does the boiling point increase or decrease the further down group 0?
Increases
Does the density of the atom decreases or increase as you go down group 0 and why?
increase because larger atoms take up more space so it makes it a stable element
What are the elements in Group 1 called?
Alkali metals
Does the reactivity of the elements in group 1 increase or decrease going down the group?
increase
What are the elements in Group 7 called?
halogens
What are halogens?
non metals and consist of molecules made of pair of atoms