chemistry quiz atomic structure Flashcards
Dalton’s theory
-every atom in an element is the same size
-contradicted by modern theory
modern theory
same size atoms are in different groups (atoms of elements are grouped based on their abundance in nature)
the modern theory is a cloud model, meaning..
electrons closer to the nucleus are more dense
to find electrons from charge:
if the charge is positive, subtract the number from protons
if charge is negative, add the number from the protons
mass =
protons + neutrons
(m=p+n)
neutrons =
mass - protons
(n=m-p)
beta particles are also known as
electrons
thomsons theory
Thomson described the atom as a ball of positive charge containing a number of electrons
rutherfords observations and conclusions:
- observation: he observed the alpha particles went through, and the gold light was showing on the screen (most of the particles went through the gold foil)
conclusion: the atoms must have been mostly empty space
- observation: a few of the alpha particles deflected
conclusion: these alpha particles were close to a positive charge in the atom
- observation: a few of the alpha particles bounced back
conclusion: those alpha particles hit the massive part of the atom
Bohr’s theory
after rutherfords discovery, Bohr proposed that electrons travel in definite orbits (shells) around the nucleus
what is inside the nucleus
protons and nuetrons
the charge of the nucleus is always
positive bc of the protons
using table o, what are the masses and charges of protons, neutrons, and electrons
protons:
mass - 1
charge - 1
neutrons :
mass - 1
charge - 0
electrons :
mass - 0
charge - -1
protons are located in the ______ and their charge is _____
nucleus, positive
neutrons are located in the _____ and their charge is ______
nucleus, neither positive or negative
electrons are located in the ______ and their charge is _____
orbits (shells), negative
atoms are mostly made up of
empty space
x
_____
x
identify
mass - x
_____
charge - x
isotopes are
atoms that have the same number of protons but different number of neutrons
atomic number and _______ are the same thing
protons
electrons are usually opposite reciprocals of the __________
atomic number/protons
calculating average mass (for isotopes):
(relative abundance x atomic mass)
_________
100
magic numbers are ____ and ____ and they…
8 and 2
make an atom stable
0 ) ) ) ) )
which shell has the highest energy and which has the lowest
the shell closest to the nucleus has the lowest energy and the shell farthest from the nucleus has the highest energy
an excited atom means
absorbs energy
how to get electrons from the periodic table
all the electron configuration numbers added up is the total number of electrons
when a electron gets excited, you don’t _______________ but when it goes back to its ground state ___________
see anything
it releases its energy in the form of light
excited state doesnt have the same _________ but same amount of _________
energy
electrons
nucleons are
what is in the nucleus (particles)
ions are
when electrons change
mass deals with…
protons and neutrons
|
v
nucleus
|
v
isotopes
(because of the difference in neutrons)
to find neutrons
atomic mass - protons
charge deals with….
proton and electron
+ –
proton = electron
+10 -10
nuclear charge - positive from the proton
excited electrons….
never change
kernel of an atom
all parts of the atom except valence
to find electrons:
add or subtract atomic number by charge
neutral atom:
electrons and protons are equal but opposite signs
mass has nothing to do with
electrons
to make an ion it has to
have magic numbers
the last electron in the electron configuration is the
valence electron
