STRUCTURE OF THE ATOM
Frequently Asked Questions
Atoms have a nucleus made of protons and neutrons, with electrons arranged in shells around it.
James Chadwick discovered the neutron in 1932.
Protons, neutrons, and electrons.
The number of protons in the nucleus of an atom.
The sum of protons and neutrons in the atom’s nucleus.
Atoms of the same element with different numbers of neutrons.
Atoms of different elements with the same mass number but different atomic numbers.
The number of electrons an atom can gain, lose, or share to become stable.
Electrons revolve in fixed orbits (shells) around the nucleus without losing energy.
Atomic number is protons; mass number is protons + neutrons.
Electrons fill shells in order, with each shell holding up to \(2n^2\) electrons.
J.J. Thomson.
The gold foil experiment.
Electrons in the outermost shell of an atom.
They have the same number of protons and electrons.
It explains element properties and reactions.
The outer electrons decide bonding and reactivity.
They add mass and stability to the nucleus.
Mass number is top left, atomic number is bottom left of the symbol (e.g.,\(^{14}_{7}\mathrm{N}\)).
Used in imaging and treatments, like radioactive iodine.
Number of protons (atomic number).
Did not explain atomic stability or electron energy levels.
Each shell can hold a max of \(2n^2\) electrons.
Arrangement of electrons in different shells.
Yes, such as mass and stability.
By increasing atomic number.
It sets up electron arrangement and reactivity.
Their outer shells are completely filled, making them stable.
Isotopes: same element, different mass; isobars: different elements, same mass.
From Dalton to Bohr, models changed with new discoveries.
Bonds are formed by gaining, losing, or sharing outer electrons.
It’s the specific arrangement of electrons in atomic shells or energy levels.
It represents whole protons and neutrons, which are counted as whole particles.
The electronic arrangement with electrons in the lowest possible energy levels.
A period is a row; a group is a column, indicating similar electronic configuration patterns.
