Atomic Structure... Flashcards
element
substance that can’t be broken down into simpler substances
each element is made up of how many atoms
one
what makes each element different from each other
the number of protons
the periodic table lists
all of the elements currently known
relative masses of the 3 sub-atomic particles in an atom
electron 0/ proton 1/ neutron 1 amu
atom
smallest part of an element that still retains the uniqueness of that element
atoms are (size)
extremely small, a few 10 billionths of a meter
the atom consists of a ____ at the center
nucleus
what circles the nucleus in different orbits
electrons
all atoms consist of 2 main regions, what are they
nucleus, electron cloud
nucleus
small, dense, central part of an atom
the nucleus is ___ charged
positively charged
the nucleus makes up the entire __ of an atom
mass
electron cloud
the region in an atom surrounding the nucleus
all atoms are made up of 3 particles, they are
protons, neutrons, electrons
protons
positive, found in nucleus & with neutrons
neutrons
neutral, found in nucleus & with protons
electrons
negative, found in electron cloud
the positive charge of protons & negative charge of electrons create the ______ _____
electromagnetic force
what does the electromagnetic force do
bind the atoms together
the amount of protons & neutrons in an atom are
equal
the atom is electrically ____
neutral
theories
sum up hypothesis which explain why/how things happen that have been hold to show true with repeated testing
theories are not ____ but they are generally expected to be true
facts
laws
sum up a body of observations to explain what will happen in certain conditions ** without trying to explain why it will happen.
atomic theory
we can’t observe the structures of atoms, so indirect evidence has been used to develop models of the atom
dalton discovery
“Billard Ball” solid atoms are the building block of all matter.
dalton experiment
mixtures of gases to see what effect the individual gases making up the mixture had on the mixture as a whole
dalton new atomic theory
each type of atom is represented by a tiny solid sphere with a different mass, no internal structure
Thompson discovery
“Plum Pudding” electron is discovered
Thompson experiment
sealed gas tubes that had metal plates on each end. when connected to electrical source a beam formed. beam bent away from neg charged plate and towards the pos plate
thompson new atomic theory
an atom is a positively charged sphere which has negatively charged electrons spread evenly about its surface
rutherfords discovery
“Classical Solar System” atoms have a nucleus
Rutherfords experiment
sent a narrow beam of alpha particles through a thin sheet of gold
rutherfords new atomic theory
that there is a nucleus to an atom which contains positively charged protons & electrons circling the nucleus
bohr discovery
“shell” electrons travel in fixed orbits around the nucleus
bohr new atomic theory
electrons move with constant speed in fixed spherical orbits around the nucleus
current electron cloud model
“quantum mechanical” nucleus is surrounded by electron cloud
overall charge of all atoms
neutral
what makes carbon an element (opposed to a compound)
1 type of atom. It cannot be broken down simpler. A compound contains atoms of different elements.
How does the element carbon structurally differ from any other element
The number of protons is unique to carbon. There are 6.
mass number is not…
on the periodic table
how to calculate mass number
of protons + # of neutrons
this model was developed based on the evidence that the atom has a dense nucleus at the center
Rutherford
this model was developed based on the evidence that all matter was made of atoms, or solid spheres
Dalton
this model was developed based on the evidence that there is a negatively charged particle in an atom
Thompson
this model was developed based on the evidence that electrons travel in fixed orbits around the nucleus
Bohr
this model was developed based on the evidence that electrons are more likely to be located in certain regions more so than others
Electron Cloud
every element has a different number of ____ which makes it unique
protons
The periodic table organizes elements into ____ & ____-
families and periods
families
vertical columns (up and down)
periods
horizontal rows
The top number on a periodic square
atomic number
Letter abbreviation on periodic square
element symbol
number on the bottom of a periodic square
atomic mass
atomic number-
number of protons in an atom of that element, will also be the # of electrons
element symbol-
1st letter always capitalized, 2nd lowercase
atomic mass-
average mass of an elements atom.
mass number-
mass of an individual isotope of an element (by adding protons and neutrons together AMU)
AMU stands for
atomic mass units
How to find number of neutrons
either
mass #-atomic # OR
rounded atomic mass - atomic #
how to find most common mass #
round atomic mass
what are both parts of this example: Hydrogen-1
name of element- mass number
isotope
atoms of the same element that have different numbers of neutrons & mass numbers
each proton and neutron add
one amu each
2 ways to show an isotope
1- the name of the element- mass number
2- chemical symbol (letter) of the element with mass number on top & atomic number on bottom
most elements have more than one ____
isotope
how to calculate atomic mass
(# of 1st isotope x mass number of isotope given after dash) + (# of 2nd isotope x mass of isotope given after dash) / # of 1st isotope + # of 2nd isotope
we know the most common isotope of blank is because
of calculating the average mass of the
mixture of its isotopes
The bohr model of the atom is referred to as
the planetary model
the bohr model is not the current model, but
its one to easily draw and use to show key characteristics of an atom
in the bohr model the nucleus shows
the amounts of protons and neutrons P= N=
1st orbital can hold how many electrons
2
2nd & 3rd orbital can hold how many electrons
8 each
the orbitals must be filled in
order, can’t add electrons to the 2nd orbital till there is 2 electrons on the first orbital
how many elements of this element have this mass? (example)
none, no two elements are the same
can this element have another atomic number? (example)
no, the amount of protons identify the element.
charge of the electron cloud is
negative
how do you name an isotope
ex. silicon-29
what is the mass number of silicon-29
29
why can the element pictured above have an isotope with a different mass number?
because there can be a different amount of neutrons
most common isotope is the same as saying
the rounded atomic mass
how do you know this is the most common isotope of an element?
averages are always closer to what there is more of
the amount of ___ always stays the same, the amount of ___ can vary
protons, neutrons
what does the atomic mass tell us about an element
the average mass of the mixture of its isotopes
how many types of atoms make up an element
one
what makes an element an element
elements are made up of one type of atom that can’t be broken down
amount of protons make the elements
differ from each other
what is a valence electron
electrons that are located on the outermost orbital of an atom
Why do some elements not want to form bonds with anything else?
if its full it won’t be able to share electrons
Which elements don’t want to form bonds and what do we call them
Nonmetals- Noble gasses
why do some atoms gain or loose electrons
so they become more stable
what do the dots on an electron dot diagram represent
valance electrons
to find the energy level/orbitals of an atom you must
count from the highest square on the periodic table ( either hydrogen or helium) and count by one for each row until you get to the row of that element
atoms want to be
stable
to be stable atoms need to have
completely filled the outermost orbital
ALL family 8 elements are ___ &
stable & do not react easily with other elements
atoms that do not have their outer orbital filled completely want to
gain or lose electrons to become stable
atoms that want to gain electrons
have 5,6 or 7 electrons on outermost energy level
atoms that want to lose electrons
have 1,2,or 3 electrons on outermost energy level
metalloids located
alongside stair step line
metals located
to the left of stair step line
non metals located
to the right of stair step line
atomic radius increases from
the right & also down. (highest on the left, the lower down the element is the higher)
valance electrons are identified by
the number on top of the table column. The column/family the element is in
atomic radius is
the size of the atom
reactivity
this is the tendency for an element to undergo a chemical change.
reactivity on the periodic table- Highest reactivities are associated with what elements
elements that most want to gain or lose electrons
metals reactivity tends to (R & L)
increase as you move from the right to the left. (highest at left side)
metal reactivity tends to (Up & Down)
increase as you move down a column (lowest highest)
non metals reactivity trends (R & L)
increase as you move from right to left (highest left side) as you move L-R more protons are present
Non metals reactivity trends (Up & Down)
increases as you move up a column (Highest Highest)
Elements that are non reactive at all
the noble gases (Family 8)
what causes the general trends of atomic radii
more protons are present in the atoms nucleus
what causes the general trends in reactivity
reactivity becomes larger because there is less distance between protons and outer electrons
atomic radius increases
from right to left ; and down
metal reactivity increases
from right to left; down
electron dot diagram
diagram that are used to represent the structure of an tom, mostly focusing on valance electrons
