Chemistry Part 2 ATOMS Flashcards
Atom
The building blocks of everything in the universe, matter is made of atoms
Sub-atomic particles of the atom
Protons (p+) - positive charge - mass=1 - inside nucleus
Neutron (n0) -neutral charge - mass=1, inside nucleus
Electrons (e-) - negative charge - mass= 1/2000 of a proton - orbits nucleus
element
a pure substance made of one type of atom and cannot be broken down by physical means
Periodic Table
- created by Mendeleev
- organized by similar physical properties and atomic numbers
- 118 elements
- shows an elements symbol, first letter is capitalized
- made up of periods and groups
Metals on the periodic table
- on the left
- conduct heat and electricity
- ductile, malleable, and lustrous
Metalloids on the periodic table
- along the amphoteric line
- properties of both metals and non metals
Non metals on the periodic table
- insulate
- on right side of table
- plus hydrogen
Alkali Metals
- group 1
- most reactive
- soft silver gray metals
Alkaline Earth Metals
- group 2
- not as reactive as group 1 but reactive
- harder than group 1
Transition Metals
- groups 3-12
- low reactivity
Halogens
- group 17
- most reactive non metals
- rarely found in elemental form
Noble Gases
- stable
- colourless
- odourless
- tasteless
Hydrogen
- non metal
- lightest of the elements
- gas at room temperature
periods in periodic table
- thé horizontal rows
- 7 periods
- elements in a period have the same number of shells
- top row is lanthanides
- bottom row is antinides
Democritus
- pounded up materials into smaller and smaller particles that he called atoma
- proposed that atoms are diff sizes, constant motion and separated by empty spaces
Aristotle
rejected the idea of atoms
- matters is made of water fire air earth
- accepted for 2000 years
John Dalton
- all matter is made up of tiny spheres that bounce around w/ elasticity
- called em atoms
- atoms of same element have the same mass and size, but diff elements are diff
- compounds are created when atoms of diff elements link
Joseph J Thompson
- atoms eject small particles called ELECTRONS
- used an electric current to determine its charge
- plum pudding model (electrons float in positive soup)
Ernest Rutherford
- detailed model w central nucleus
- nucleus has small dense positive charge and attracts electrons
- discovered protons
- experiment: fired positive particles at a thin sheet of gold foil. Some passed through, deflected and some bounced straight back
James Chadwick
- neutrons (no charge)
- atom is empty sphere dense central nucleus
- nucleus has protons and neutrons
- mass of neutrons = mass of protons
- electrons circle nucleus
- neutral atom has same number of protons and electrons
Noël Bohr
- électrons are in orbits
- has fixed energy
- can not jump between orbits
- can jump to another orbit
- orbits have a max # of electrons:
1st orbit = 2 electrons
2nd orbit = 8 electrons
3rd orbit = 8 electrons
Thé atom structure
- nucleus w protons and neutrons
- electrons orbit
Atomic number
- shows the number of protons and electrons in a neutral atom
-identifies atom
Atomic mass
= protons + neutrons
and
neutrons = atomic mass - protons
standard atomic notation
- atomic number below symbol
- atomic mass above symbol
Ions
an atom that is charged (has gained or lost electrons)
Cation
A positively charged ion (lost electrons)
Anion
negatively charged ion (gained electrons)
calculate overall charge
overall charge = #protons - #electrons
Isotope
an atom of the same element with a different number of neutrons (diff atomic mass)
molecular compound
a molecule that consists of two or more different elements
molecular element
a molecule that is made up of two atoms of the same element
ionic compound
a compound that consists of positively and negatively charged ions (non metals and metal)
(like trade electrons)
