Studied by 3 people
what is the nucleus made up of
protons and neutrons
what charge does a nucleus have
it has a positive charge because of the protons
what charge are electrons
they are negatively charged
what does the atomic number tell you
how many protons there are
what does the mass number tell you
how many protons and neutrons there are
how do you find the number of neutrons
subtract the atomic number from the mass number
what is an element
a substance made up of atoms that all have the same number of protons in their nucleus
molecules definition
contains 2 or more non-mental atoms
element definition
contains SAME atoms
compound definition
contains different elements chemically combined
what are isotopes
Atoms of the same element with different numbers of neutrons.
what is the formula to find relative atomic mass
what was the plum pudding theory
J.J. Thomson in 1904 said it was a positively charged sphere with electrons embedded throughout
what was ernest rutherfords theory/ the alpha particle theory
Theory that atoms have a small, positively charged nucleus surrounded by negatively charged electrons orbiting in shells. The nucleus contains most of the atom's mass and is held together by strong nuclear forces.
how many electrons can be in the 1st shell
2 electrons
how many electrons can be in the 2nd shell
8 electrons
how many electrons can be on the 3rd shell
8 electrons
how do you work out the electronic structures
Find the atomic number of the element
Determine the number of electrons by balancing the charges
Arrange the electrons in energy levels, starting with the lowest
Fill each energy level with the maximum number of electrons
Write the electronic configuration in shorthand notation using the noble gas configuration of the preceding element.
how did dmitri mendeleev arrange the periodic table
Mendeleev organized the periodic table by atomic mass and properties, leaving gaps for unknown elements and predicting their properties.
how is the periodic table arranged in modern day
its its arranged in an increase of atomic numbers
what is group 1 also known as
alkali metals
what are some characteristics of group one
.all have 1 electron on the outer shell
.increasing reactivity- outer electron is more easily lost
.atoms get larger as you go down the group 1
.lower melting and boiling points
what happens when group 1 reacts with water
it vigorously produces hyrdogen gas
what is group 7 also known as
halogens
what are the trends of group 7
.become LESS REACTIVE
.have HIGHER melting and boiling points
.have HIGHER relative atomic mass
what is it called when halogens join together
diatomic molecules
what is group 0 also known as
noble gasses
what are some characteristics of noble gasses
.all have 8 electrons on outer shell
.they are inert
what are the trends of noble gasses
.boiling points of noble gasses INCREASE
mixtures definition
different substances NOT chemically combined
what is the green house effect
The process by which greenhouse gases trap heat in the Earth's atmosphere, leading to warming of the planet.
what are the three main green house gasses
water vapour, carbon dioxide and methane
what are some human activities that produce green house gasses
burning fossil fuels, cutting down forests and farming live stock
exothermic definition
reaction that gives out hear to the surrounding
endothermic definition
reaction that takes in heat from the surroundings
do metals lose or gain electrons to make a full outer shell
metals lose electrons to create positive ions
do non-metals lose or gain electrons to make a full outer shell
non-metals gain electrons to form negative ions
what side of the periodic table contains non-metals
the left side
Note 
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