Chemistry - The Atomic Model Flashcards
What is the nucleus?
A very small and dense part at the centre of the atom. It contains positively charged protons and neutral neutrons.
What is the charge of the nucleus?
Positive
Protons
Positively charged nucleons with a mass of 1 a.m.u.
Equal but opposite to the charge of a proton
Electron (Negative charge)
Neutron
Same size as proton and has a mass of 1 a.m.u. No charge.
Electron
Negatively charged, with a very small mass.
In a neutral atom, the number of _____ is equal to the number of _______.
… protons … electrons …
A.m.u.
Atomic Mass Units - mass of atomic particles since they are not measured in grams
Atomic Number (Z)
Number of protons in an atom, thus in a neutral atom it would show the number of electrons as well
Relative Atomic Mass (A)
Number of Nucleons in an Atom
Protons + Neutrons
Thus, A - Z = Number of Neutrons
Isotopes
These are atoms of the same element with different numbers of neutrons. Most atoms have two or more of these
What is Electron Configuration?
The way in which electrons are arranged in energy levels around the nucleus
In what do electrons move around the nucleus in?
Energy Levels
Why are electrons grouped in a specific energy level?
They have that specific amount of energy
What does the distance of an electron from the nucleus tell us about its energy?
The further the electron is from the nucleus, the more energy.
How do electrons move through energy levels?
They absorb or lose energy, thus moving up or down respectively
What is the ground state?
The lowest energy level
The s-subshell
1 orbital that has a spherical shape
The p-subshell
3 p-orbitals which are all hourglass shapes. They are labelled Px, Py & Pz, respectively.
How many electrons can a single orbital hold?
2
Pauli’s Exclusion Principle
Only 2 electrons fit in an orbital
Hund’s Rule
If an electron can be alone, it prefers to do so
Periodic Law
Physical and Chemical Properties of the elements vary periodically with increasing atomic mass
