Studied by 2 people________- the particles that determine the identity of an element.
Protons
Negative charge, -1 g (amu), outside the nucleus.
Electrons
________= discovered the nucleus; did the gold leaf expierement
Rutherford
Individual building blocks of matter; pieces of elements from the table.
Atoms
the particles found in the nucleus.
Protons and neutrons
Anything made up of at least 2 non- metal atoms; can either be the same element.
Molecules
Proposed atoms are made of earth
Greeks
Worked with cathode ray and discovered that the rays are deflected by electric and magnetic fields
Jj thomson
Discovered the neutron
Chadwick
Identified the electron
Jj thomson
positive charge, 1+ g (amu), inside the nucleus
Protons
neutral charge, 0g (amu), inside the nucleus
Neutrons
Protons + neutrons
mass number
Protons + electrons
Net force/charge
Which particles affect the charge of an atom or ion
Electrons
Element symbol
What is normally in place of A
Net force/charge
What is normally in place of b
atomic number
what is normally in place of c
Atomic mass
What is normally in place of d
3
What is the atomic mass
2
What is the atomic number
+1
What is the charge
1
How many neutrons are there
2
How many protons are there
1
How many electrons are there
What two things must be true for an element to be an isotope
Diff number of neutrons/mass and the same number of protons/same element
An atom or molecule that gained or lost electrons
Ion
a positively charged ion; an ion that has lost electrons
cation
a negatively charged ion; an ion that has gained electrons
anion
What are the two forces that work in the nucleus
Strong nuclear force and electromagnetic repulsion
How do u calculate molar mass
Add together the molar mass from each individual atom in the compound (found on periodic table)
What are the units for molar mass
G/mol
What is the formula for calculating AAM
AAM= A(%A)+ B(%B) +…
In what order do u convert mass to atoms (mmpa)
Mass, mols, particles, atoms
What are the units for average atomic mass
amu
How do all atoms of the same element react
Chemically the same
proposed that atoms weren’t indivisible, but made up of smaller partciles called subatomic particles (proton, neutron, electron)
thomson
what did dalton’s atomic theory state and how does it relate to modern science
states all matter is made of tiny indivisible particles called atoms (proven wrong) ◦ modern science: atoms are not indivisble
atoms of the same element are exactly alike + have same mass; atoms of different elements have different masses ◦ modern science: concept of isotopes —> not quite right
in chemical reactions, atoms are combined, separated, or rearranged
atoms of diff elements combine in whole-number ratios to form chemical compounds
who developed the law of multiple proportions which states that when elements form compounds, the proportions of the elements in those chemical compounds can be expresses in small whole number rations (elements on the periodic table)
dalton
conducted experiments to determine the charge-to-mass ratio and the mass of the electron
milikan
found out that the electron is 9.109x10^-31kg
milikan
◦ found out that all atoms are able to produce electrons and atoms are not indivisble
milikan
determined the magnitude of electron charge
milikan
found that most alpha particles passed through, some angled slightly, and a tiny fraction bounced back
rutherford
found out that atom is mostly empty space, (+) particles are concentrated at the center of the nucleus (little nut), and that (-) particles orbit the nucleus
rutherford
who found out the purpose of the neutrons
chadwick
what is the purpose of neutrons
to stabalize the nucleus
◦ danish physicist proposed a model of the atom in which the electrons orbit the nucleus without losing energy ◦ calls each possible orbit a quantom ◦ based his theory on the work of planck ◦ proposed that light is made up of units of energy of a definite amount, each of which is called a energy level
bohr
a group of elements that have the same amount of protons but different masses/# of neutrons
isotopes
what is the difference between atoms and molecules
atoms are singular neutral particles molecules are bonded neutral atoms (2 or more atoms)
Note
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