C1 Chemistry Flashcards
(43 cards)
What is an element?
A substance made from only one type of atom.
How are elements arranged in the periodic table?
By atomic number.
What are groups in the periodic table?
Vertical columns of elements with similar chemical properties.
What are periods in the periodic table?
Horizontal rows where elements have the same number of shells.
What is a compound?
Two or more elements chemically bonded together.
What is a mixture?
A combination of substances not chemically bonded.
Give an example of a compound and a mixture.
Compound: H₂O; Mixture: Air.
What is the law of conservation of mass?
Mass is not created or destroyed in a chemical reaction.
Why might mass appear to change in a reaction?
A gas may escape or enter from the air.
Why do chemical equations need to be balanced?
To show the same number of atoms on both sides of the reaction.
Balance the equation: H₂ + O₂ → H₂O
2H₂ + O₂ → 2H₂O
What is chromatography used for?
Separating dissolved substances, e.g. inks.
What is distillation used for?
Separating liquids based on different boiling points.
What is crystallisation used for?
Separating a dissolved solid by evaporation.
What is a pure substance?
A single element or compound.
What is an impure substance?
A mixture of different substances.
What is the relative charge of a proton?
+1
What is the relative charge of a neutron?
0
What is the relative charge of an electron?
-1
Where are protons and neutrons found in an atom?
In the nucleus.
Where are electrons found in an atom?
In energy levels (shells) around the nucleus.
What is the atomic number?
Number of protons in an atom.
What is the mass number?
Total number of protons and neutrons.
How do you calculate number of neutrons?
Mass number – Atomic number.
