Unit 1 Flashcards
Particle theory of matter
John Dalton
1) All matter is made up of particles
2) Atoms can’t be broken down further
3) Atoms can be rearranged with each other
4) Atoms of the same element are the same
Valance shell
Outermost shell, only electrons that can change
Atomic number
Number of protons and electrons
Atomic mass
Total mass of protons and neutrons. Atomic mass- atomic number = number of neutrons
Octet rule
Atom is most stable with a full shell of electrons
Ions
Atoms that become charged through chemical bond s
Anion
Negative, gains electrons. Non metals
Cations
Positive, looses electrons. Metals
Isotopes
A form of an element where the number of protons stays the same but the number of neutrons changes
Isotopic abundance
What % of an isotope exists. Average atomic mass= (iso1)x+ (iso2)(1-x)
Periodic law
If they are in the same column, they react the same because they have the same number of valence electrons. The further down you go, the more reactive you get
Necular strength
The more protons, the greater the charge and make the atomic radio smaller because they draw electrons in
Ionization energy
The amount of energy required to pull electrons away from an element
Electron affinity
Energy change when a neutral atom gains an electron
Electronegativity differences
The amount of energy required to pull electrons away from other atoms
Ionic electronegativity difference
Greater then 1.7
Polar covalent
1.7-0.5
Covalent (non polar)
Below 0.5
Radioactive decay
When unstable isotopes all of a sudden disintegrate
Most common types of necular radiation
Alpha particles- Positively charged. Same structure of the nucleus of a helium atom. Slow moving
Beta particle- Negatively charged, identical to an electron. Fast moving
Gamma ray- High energy, electromagnetic. Fast moving
When a molecule is polar it has….
Unequal sharing of electrons
When a molecule is not polar is has…
Equal sharing of electrons
Diatomic gasses
Hydrogen, oxygen, nitrogen and column 17
Intermolecular forces
Weak attractions between particles, not even 1/100 as strong as a bond
Vander walls forces
Hydrogen bonding >dipole dipole> londen dispersion force
Hydrogen bonding
H atoms are attracted to highly electronegative atoms (NOF)
Dipole dipole forces
Attraction between the partial positive and negative charges of polar molecules
Londen forces
The electrons in one molecule are attracted to the protons in another molecule. They are typically exhibited in non polar molecules. Happens because of temporary un balance of electrons. The more electrons, the greater the charge
John Dalton
Billiard Ball model
J.J. Thompson
Plum pudding model, discovered the electron
Ernist Rutherford
Discovered the nucleas and protons
Chadwick
Discovered neutrons
Neils Bohr
Discovered hydrogen has a unique arrangement and that electrons orbit the atom
When is ionization energy low
When the atomic radius is large therefore the electron s are far away from the nucleus (atomic radius increases with ionization energy and electron affinity)
