C 1 The fundamental ideas in chemistry Flashcards
(20 cards)
What is an atom?
The smallest particle of an element that still retains the properties of that element.
What is the structure of an atom?
An atom has a nucleus containing protons and neutrons, surrounded by electrons in shells.
What is the relative charge of a proton, neutron, and electron?
Proton: +1
Neutron: 0
Electron: -1
What is the relative mass of a proton, neutron, and electron?
Proton: 1
Neutron: 1
Electron: ~0 (1/1836)
What is the atomic number?
The number of protons in the nucleus of an atom.
What is the mass number?
The total number of protons and neutrons in an atom’s nucleus.
What are isotopes?
Atoms of the same element with the same number of protons but different numbers of neutrons.
How are electrons arranged in atoms?
In energy levels or shells around the nucleus:
1st shell: max 2 electrons
2nd shell: max 8
3rd shell: max 8 (for GCSE level)
Why are atoms neutral?
Because they have the same number of protons (positive) and electrons (negative), balancing the charges.
What is a compound?
A substance made from two or more elements chemically bonded together.
How do atoms bond in compounds?
Through either ionic or covalent bonding.
What happens in ionic bonding?
Electrons are transferred from one atom to another, forming positive and negative ions.
Which types of elements form ionic bonds?
Metals and non-metals.
What happens in covalent bonding?
Atoms share pairs of electrons to achieve full outer shells.
Which types of elements form covalent bonds?
Non-metals only.
What is a molecule?
Two or more atoms bonded together covalently.
What is a chemical formula?
A representation showing the types and numbers of atoms in a compound.
What is a chemical equation?
A representation of a chemical reaction using symbols and formulae.
Why must chemical equations be balanced?
Because atoms are not created or destroyed in chemical reactions (Law of Conservation of Mass).
What are ions?
Charged particles formed when atoms lose or gain electrons.
