Chemistry · Atomic Structure
Describe the structure of the atom as mostly empty space surrounding a very small nucleus that consists of protons and neutrons and state that electrons are found in shells in the space around the nucleus
Identify and describe protons, neutrons and electrons in terms of their relative charges and relative masses
Use and understand the terms atomic (proton) number and mass (nucleon) number
Deduce the behaviour of beams of protons, neutrons and electrons moving at the same velocity in an electric field
Understand that ions are formed from atoms or molecules by gain or loss of electrons
Deduce the numbers of protons, neutrons and electrons present in both atoms and ions given atomic (proton) number, mass (nucleon) number and charge
Define the term isotope in terms of numbers of protons and neutrons
Explain why isotopes of the same element have the same chemical properties
Explain why isotopes of the same element have different physical properties (limited to mass and density)
Number of neutrons
Used to calculate the number of neutrons in an atom or isotope.
Students often think atoms are solid spheres, but actually they are mostly empty space.
Students often confuse atomic number with mass number, leading to errors in calculating neutrons.
Students often think isotopes have different chemical properties, but actually their chemical properties are the same due to the same number of electrons.
Students often think ions are formed by gaining or losing protons, but actually ion formation always involves the gain or loss of electrons.
Students often think electrons are stationary in shells, but actually the shell model is a simplification; electrons occupy probability regions called orbitals.