AQA GCSE CHEMISTRY PAPER 1 QUESTIONS
WITH CORRECT ANSWERS 2025-2026
What is an *atom*? - CORRECT ANSWER -smallest part of an element
What is an *element*? - CORRECT ANSWER -a substance that contains only one type of atom
What are *chemical symbols*? - CORRECT ANSWER --
the letter or pair of letters that represents an element.
- first letter is always capitalized
What are *compounds*? - CORRECT ANSWER -
substances in which atoms of two or more elements, which are chemically combined
What is a *chemical formula*? - CORRECT ANSWER -
a combination of symbols that shows the ratio of elements in a compound
Why are *chemical formula* used? - CORRECT ANSWER -- the different elements in a compound
- how many atoms of each element one molecule of the compound contain
How can *compounds* be separated? - CORRECT ANSWER -Through chemical reactions
What are *reactants*? - CORRECT ANSWER -the starting materials in a chemical reaction (on the left)
What are *products*? - CORRECT ANSWER -the ending materials in a chemical reaction (on the right)
What is always *equal* to each other in a *chemical reaction*? - CORRECT ANSWER -
products to reactants
- no atoms are lost or made
,What is a *mixture*? - CORRECT ANSWER -
consist of two or more elements or compounds which are not chemically combined
What are the *properties* of *mixtures*? - CORRECT ANSWER -
they retain their own properties from before
e.g. colour
How can *mixtures* be separated? - CORRECT ANSWER -by physical processes -
no new substances are made
What is *filtration*? - CORRECT ANSWER --Bused to separate soluble solids from insoluble solids
What is *crystallisation*? - CORRECT ANSWER -- used to obtain a soluble solid from a solution
1. Mixture is gently warmed
2. Water evaporates leaving crystals of pure salt
What is *simple distillation*? - CORRECT ANSWER -used to obtain a solvent from a solution
*RP* Analysis and purification of water samples from different sources - CORRECT ANSWER -
1. Use a pH probe or indicator to analyse the pH of the sample
2. Set up the equipment
3. Heat a set volume to 100oC so that the water changes from liquid to gas
4. Water collects in the condenser and changes state from gas to liquid
5. measure the mass of solid that remains to find the amount of dissolved solids present in the sample
What is *fractional distillation*? - CORRECT ANSWER --
used to separate mixtures in which the components have different boiling points
What is *chromatography*? - CORRECT ANSWER -
used to separate the different soluble, coloured components of a mixture
,What were *atoms* thought to be in *early models*? - CORRECT ANSWER -
Tiny spheres that could not be divided into simpler particles
What did *Thomson* discover in 1898? - CORRECT ANSWER -electrons -
causing the representative of atoms to be changed
What model did *Thomson* make ? - CORRECT ANSWER -plum pudding model
What was the *plum pudding* model made up of? - CORRECT ANSWER --
atom contained tiny, negative electrons
- surrounded by a positive charge
What did *Geiger and Marsden* do? - CORRECT ANSWER -
measured the deflection of alpha particles bombarding gold foil
What did *Geiger and Marsden* conclude about their experiment? - CORRECT ANSWER --
some alpha particles deflected
- some went straight through
What did *Rutherford* conclude about the *alpha and gold foil* experiment? - CORRECT ANSWER --
there must be a positive charge in the center of each atom (new model now called 'nuclear')
What did *Bohr* do? - CORRECT ANSWERB-
said that electrons were arranged in levels or orbits around the nucleus
What did *James Chadwick* discover? - CORRECT ANSWER -neutrons in the nucleus
How big are *atoms*? - CORRECT ANSWER -- very small
- 0.1nm or 1 x 10^-10m
What do all *atoms* contain? - CORRECT ANSWER -protons, neutrons, electrons
, What is the *relative charge* and *mass* of a *proton*? - CORRECT ANSWER -1
+1
What is the *relative charge* and *mass* of a *nucleus*? - CORRECT ANSWER -1
0
What is the *relative charge* and *mass* of an *electron*? - CORRECT ANSWER -very small
-1
Where is most of the *mass* of an *atom*? - CORRECT ANSWER -nucleus
How much *smaller* is the radius of the *nucleus* compared to the rest of the atom? -
CORRECT ANSWER -1/10000
Why do *atoms* have no *overall charge*? - CORRECT ANSWER -
they contain an equal number of protons and electrons
What do all atoms of a particular *element* have in common? - CORRECT ANSWER --
they have the same number of protons
What is the *atomicBnumber*? - CORRECT ANSWER -number of protons
What is the *mass number*? - CORRECT ANSWER -Number of protons and neutrons
What are *isotopes*? - CORRECT ANSWER -
Atoms of the same element with different numbers of neutrons
How can *atoms* become *ionic*? - CORRECT ANSWER -- by losing or gaining electrons
WITH CORRECT ANSWERS 2025-2026
What is an *atom*? - CORRECT ANSWER -smallest part of an element
What is an *element*? - CORRECT ANSWER -a substance that contains only one type of atom
What are *chemical symbols*? - CORRECT ANSWER --
the letter or pair of letters that represents an element.
- first letter is always capitalized
What are *compounds*? - CORRECT ANSWER -
substances in which atoms of two or more elements, which are chemically combined
What is a *chemical formula*? - CORRECT ANSWER -
a combination of symbols that shows the ratio of elements in a compound
Why are *chemical formula* used? - CORRECT ANSWER -- the different elements in a compound
- how many atoms of each element one molecule of the compound contain
How can *compounds* be separated? - CORRECT ANSWER -Through chemical reactions
What are *reactants*? - CORRECT ANSWER -the starting materials in a chemical reaction (on the left)
What are *products*? - CORRECT ANSWER -the ending materials in a chemical reaction (on the right)
What is always *equal* to each other in a *chemical reaction*? - CORRECT ANSWER -
products to reactants
- no atoms are lost or made
,What is a *mixture*? - CORRECT ANSWER -
consist of two or more elements or compounds which are not chemically combined
What are the *properties* of *mixtures*? - CORRECT ANSWER -
they retain their own properties from before
e.g. colour
How can *mixtures* be separated? - CORRECT ANSWER -by physical processes -
no new substances are made
What is *filtration*? - CORRECT ANSWER --Bused to separate soluble solids from insoluble solids
What is *crystallisation*? - CORRECT ANSWER -- used to obtain a soluble solid from a solution
1. Mixture is gently warmed
2. Water evaporates leaving crystals of pure salt
What is *simple distillation*? - CORRECT ANSWER -used to obtain a solvent from a solution
*RP* Analysis and purification of water samples from different sources - CORRECT ANSWER -
1. Use a pH probe or indicator to analyse the pH of the sample
2. Set up the equipment
3. Heat a set volume to 100oC so that the water changes from liquid to gas
4. Water collects in the condenser and changes state from gas to liquid
5. measure the mass of solid that remains to find the amount of dissolved solids present in the sample
What is *fractional distillation*? - CORRECT ANSWER --
used to separate mixtures in which the components have different boiling points
What is *chromatography*? - CORRECT ANSWER -
used to separate the different soluble, coloured components of a mixture
,What were *atoms* thought to be in *early models*? - CORRECT ANSWER -
Tiny spheres that could not be divided into simpler particles
What did *Thomson* discover in 1898? - CORRECT ANSWER -electrons -
causing the representative of atoms to be changed
What model did *Thomson* make ? - CORRECT ANSWER -plum pudding model
What was the *plum pudding* model made up of? - CORRECT ANSWER --
atom contained tiny, negative electrons
- surrounded by a positive charge
What did *Geiger and Marsden* do? - CORRECT ANSWER -
measured the deflection of alpha particles bombarding gold foil
What did *Geiger and Marsden* conclude about their experiment? - CORRECT ANSWER --
some alpha particles deflected
- some went straight through
What did *Rutherford* conclude about the *alpha and gold foil* experiment? - CORRECT ANSWER --
there must be a positive charge in the center of each atom (new model now called 'nuclear')
What did *Bohr* do? - CORRECT ANSWERB-
said that electrons were arranged in levels or orbits around the nucleus
What did *James Chadwick* discover? - CORRECT ANSWER -neutrons in the nucleus
How big are *atoms*? - CORRECT ANSWER -- very small
- 0.1nm or 1 x 10^-10m
What do all *atoms* contain? - CORRECT ANSWER -protons, neutrons, electrons
, What is the *relative charge* and *mass* of a *proton*? - CORRECT ANSWER -1
+1
What is the *relative charge* and *mass* of a *nucleus*? - CORRECT ANSWER -1
0
What is the *relative charge* and *mass* of an *electron*? - CORRECT ANSWER -very small
-1
Where is most of the *mass* of an *atom*? - CORRECT ANSWER -nucleus
How much *smaller* is the radius of the *nucleus* compared to the rest of the atom? -
CORRECT ANSWER -1/10000
Why do *atoms* have no *overall charge*? - CORRECT ANSWER -
they contain an equal number of protons and electrons
What do all atoms of a particular *element* have in common? - CORRECT ANSWER --
they have the same number of protons
What is the *atomicBnumber*? - CORRECT ANSWER -number of protons
What is the *mass number*? - CORRECT ANSWER -Number of protons and neutrons
What are *isotopes*? - CORRECT ANSWER -
Atoms of the same element with different numbers of neutrons
How can *atoms* become *ionic*? - CORRECT ANSWER -- by losing or gaining electrons
