Atomic Theory
"Atomos" means....
Can't be divided
The three particles in an atom
Electron, proton, neutron
What are the big letters in the box of the element?
element's symbol
The handsome Russian who created it on a long train ride
Mendeleev
A pure substance which cannot be separated into a simpler substance
Element
The little raisins in Thomson's plum pudding model represented...
electrons
Protons are important because they...
determine what the element is
The number at the top (usually) of the box is the ....number, and represents the number of ..... in the atom
atomic, protons
Mendeleev eventually organized his table according to what?
Atomic number
A combination of substances that are brought together only through physical means
Mixture
The parts of the atom discovered by Rutherford when he shot them at gold foil
Nucleus and protons
Neutrons are important because they...
Space out the protons and balance out the gravity of the + charges
The number at the bottom of the box is atomic ...., and can help us determine how many ..... are in the atom
mass, neutrons
How many elements have been discovered as of now?
118
A combination of substances brought together by chemical processes
Compound
We use Bohr's planet model to place/locate electrons. This is not scientifically correct. Why not, and why do we use it anyway?
electrons are in clouds and not specific places in the orbit, we still use because is easier to visualize and understand
places where atoms combine, balance the + charge of protons
There is no number for electrons in the atom. How can the number of electrons be determined?
same as protons/atomic number
Of the three classes of elements, which is the most numerous on the periodic table?
Metals
Name three ways a mixture can be separated
Boil, pick out, magnet, spin/motion, sift/filter
All three parts of Dalton's atomic theory
1: all things are made of atoms 2: atoms of same element are exactly alike 3: atoms join with other atoms to make new substances
What are the two things that can happen when a neutron is taken out of an atom (isotope)?
Nothing, radioactive
The element Gallium (Ga) has an atomic number of 31. How many electrons are in its outer shell?
5
Mendeleev only knew of 58 elements. How then did he explain the gaps in his table when he created it?
elements not discovered yet, properties repeat themselves in periods, knew what the characteristics of the elements in the gaps would be
Name two ways to separate the elements in sugar or salt
Electricity, extreme heat