Chapter 2 Flashcards
Atomic Structure
Protons and Neutrons are inside the nucleus whilst electrons whizz around the Nucleus
Protons
A subatomic part of an atom, with a positive charge, found inside the nucleus
Neutrons
A subatomic part of an atom with, a neutral charge, found inside the nucleus
Electrons
A subatomic part of an atom with, a negative charge free, whizzing around the nucleus
Atomic Number
the number of protons in the nucleus of an atom
Atomic Mass/ Mass number
The sum of protons and neutrons in the nucleus of an atom
Isotopes
Atoms of the same element, with the same number of protons but different numbers of neutrons
Ions
positively and negatively charged atoms - formed by the loss and gain of electrons
Cations
positively charged ions
Anions
negatively charged ions
Emission Spectra
Emission spectra are the different colors of light emitted by a substance when it is heated or excited.
Cause of emission spectra
Emission spectra are caused by the release of electromagnetic radiation.
Neils Bohr Proposal on electrons
Electrons move around the nucleus without losing energy.
- They follow fixed energy levels.
- Their orbit is determined by their energy.
- Electrons closer to the nucleus have lower energy.
- The outermost energy level is called the valence shell.
Bohrs Electron Shell Arangement
First Shell - K - 2
Second Shell - L - 8
Third Shell - M - 18
Fourth Shell - N - 32
The outermost shell can only ever have 8 electrons
Bohrs Electron Shell Arangement equation
Max number = 2n sqaured
Bohrs Models Complications
-Cannot accurately predict emission spectra for multi-electron atoms.
- Fails to explain why each shell holds 2n^2 electrons.
- Does not clarify why shell 4 fills with electrons before shell 3 is complete.
Schrodinger Model
A model for the behaviour of electrons in atoms. It describes electrons as having wave-like properties.
Schrodinger finindings
- Atoms have major energy levels called shells.
- Each shell contains subshells with similar energy levels.
Schrodinger electron shell holding
S - 2
P- 6
D - 10
F - 14
Schrodinger Exceptions
Copper (Cr)
Chronium (Cu)
Period Number
number of electron shells
Group Number
The number of electrons in the valence shell (outer shell)
Main group elements
Groups 1, 2, 13-18
Transitional metals
groups 3-12
Nobel Gases
Group 18 - Very unreactive
What is core charge?
A measure of attraction felt by valence electrons to the positive nuclear charge.
How is core charge calculated?
Core charge = atomic number - total number of inner shells.
How does core charge change across a period?
Core charge increases from left to right across a period.
Electronegativity
Increasing
The measure of the ability of an atom to attract electrons to itself
Increases: / (left to right, up)
Atomic Radius
size of an atom - increases right to left, downwards
First Ionisation energy
increases
The energy required to remove one electron, increases: / (left to right, up)
Reactivity of Metals - increasing
right to left, downwards
Reactivity of Non Metals - increasing
left to right, upwards
Metallic Character
a measure of how easily an element loses a valence electron, increases ( right to left, downwards)
Non Metallic Character
ability to gain electrons, increasing: left to right, upwards
