unit 2 regents Flashcards
what is an atom
the smallest characteristic particle of an element
what does the word atom stem from
the greek word atomos that means the smallest indivisible particle of matter, or something that cannot be divided.
what are molecules mode of
molecules are made up of atoms that are bonded to each other and remain intact even when the material is melted or boiled
what are the diatomic elements
hydrogen, oxygen, nitrogen, chlorine, bromine, iodine, flourine
HONClBrIF
what is a disatomic element
an element that doesnt exist on its own, but found in two atom pairs in nature.
whats the nucleus made of
protons and neutrons
what is the symbol for a proton
p+
what is the symbol for a neutron
n
what is the symbol for a electron
e-
what is the mass of a proton
1u
what is the mass of a neutron
1u
what is the mass of a electron
1/1837, or 0
what is the charge of a proton
1+
what is the charge of a neutron
0
what is the charge of a electron
1-
where is a proton located in a atom
nucleus
where is a neutron located in an atom
nucleus
where is an electron located in the atom
outside the nucleus, or in an electron “cloud”
what does the atomic number represent
the number of protons and electrons in an element
what is the symbol for an atomic number
Z
what is the mass number
sum of protons and neutrons in a nucleus
what are the units for the mass number
AMU (atomic mass unit)
what does X represent in an element
the elemental symbol
what does A represent in an element
mass number
what does Z represent in an element
atomic number
what is the number of protons always equal to
number of electrons
whats an isotope
when a element has it’s mass number changed via the change in neutrons
what changes and stays the same in an isotope
number of neutrons and mass number changes, while the atomic number and amount of protons stays the same
whats the average atomic mass of an element
the average of all masses of all naturally occurring isotopes per mole. ( relative abundance)
what is the math to find the average atomic mass of a element given the atomic mass and natural abundance of an elements isotopes?
p1 = percent in decimal 1 m1 = mass 1
p2 = percent in decimal 2 m2 = mass 2
p1(m1) + p2(m2)
ex. oxygen:
0.5721(120.9038212) + 0.4279(122.9042160) = 121.7597901
the reference tables round to 121.760.
there may be more then 1 isotope of the element given so adjust as needed
what does Bohr’s model of the atom state
that electrons are found orbiting a positively charged nucleus
what does the wave mechanical model of the atom say about electrons?
that they are found in regions of probability around the nucleus called orbitals
what did Rutherford’s model of the atom state
that electrons are found orbiting a positively charged nucleus
what did Thomson’s model of the atom state
that electrons are mixed in evenly with a positive charge
Who was responsible for the plum pudding model and cathode ray tube experiment
Thomson
who was responsible for the gold foil experiment
Rutherford
who was responsible for the light spectra and planetary model
Bohr and rutherford
what happens when a electron drops from a high to low energy level
light is released in the form of photons aka light
what happens when an electron jumps from a low to a high energy level
light is absorbed
what is responsible for emission spectra
when an electron drops from a high to low energy level, releasing photons. put the rays through a prism, and you get the spectrum.
what is responsible for a absorption spectra
when an electron climbs from a low to high energy level. Photons are absorbed, and the light remaining light has missing black bars, which represent the light absorbed.
what is a valence electron
an electron on the outermost shell of the atom.
how to make an electron enter an excited stater
make it absorb energy. one of the most common ways is heating up.
how to tell if an electron config is in-ground or excited state
if the electrons skipped filling a shell, and went to the next. this is typically an indicator of an excited atom.
