Atoms & Molecules
- It is important to understand the terms atom and molecule when referring to atomic structure, elements and compounds
Atoms & Molecules Definitions Table
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CarolineExpertise
Physics Lead
Atoms & Molecules Definitions Table
The Mass & Charge of Subatomic Particles Table
The mass of an electron can just be stated as 'negligible' or 'very small' in an exam. You do not need to learn the value.
Atomic Structure Key Terms Table
The term nucleon number is an alternative to mass number and means the same thing. A nucleon is a collective name for protons and neutrons.
Finding the protons
Mass number = number of protons + number of neutrons
Number of protons = mass number – number of neutrons
Finding the electrons
Finding the neutrons
Number of neutrons = mass number – number of protons
Determine the number of protons, electrons and neutrons in an atom of element X with atomic number 29 and mass number 63.
Answer:
Number of protons = 29
Number of neutrons = mass number – number of protons
Number of neutrons = 63 – 29
Number of neutrons = 34
to absolutely everything:
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Caroline graduated from the University of Nottingham with a degree in Chemistry and Molecular Physics. She spent several years working as an Industrial Chemist in the automotive industry before retraining to teach. Caroline has over 12 years of experience teaching GCSE and A-level chemistry and physics. She is passionate about creating high-quality resources to help students achieve their full potential.