atomic calculations cps chemistry. parts of the atom electron negative charge allows atoms to bond ...
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Neutron Neutral Charge, number can vary in nucleus Binds nucleus together 1.7x kgTRANSCRIPT
Atomic CalculationsCPS Chemistry
Parts of the atom… Electron
Negative Charge Allows atoms to bond & react 9.1x10-31kg
Neutron Neutral Charge, number can vary in nucleus Binds nucleus together 1.7x10-27kg
Proton Positive Charge unique number, gives atoms/element their
identity 1.7x10-27kg
Atomic Number A unique number which is equal to the
number of protons in the nucleus (whole number) of an element Examples
Hydrogen – 1 Lithium – 3 Oxygen - 8
Isotopes Isotopes are when there are varying
numbers of neutrons in the nucleus for a type of element
Example for hydrogen Protium – 1Proton, 0 Neutrons Deuterium – 1Proton, 1 Neutron Tritium – 1 Proton, 2 Neutrons
Nuclide – a general term for any isotope of an element
Atomic Mass The atomic mass is the sum of the masses
of the protons and neutrons in the nucleus of a atom – electrons are not counted because their relative mass is insignificant compared to the other two subatomic particles.
The atomic mass is usually expressed as a decimal because it is an average of the masses of all the isotopes for that element
How many neutrons? If the atomic number is the number of
protons in an element, and the atomic mass (round to the nearest whole number) is the number of protons + neutrons than to find the number of neutrons…
Atomic Mass – Atomic Number = # of Neutrons
Example If the atomic number for silver (Ag) is 47,
and the atomic mass is 108, how many neutrons are there?
Atomic # = 47Atomic Mass = 108
108-47 = 61 neutrons
How many electrons are there? In a neutral atom, the number of electrons
equals the number of protons
If there is a +1 next to an atom, it means that it has one less electron than protons
If there is a -1 next to an atom, it means that it has one more electron than protons
Example 2 Find the number of subatomic particles
associated with Sn+2
On the periodic table of elements Tin has an atomic number of 50, and an atomic mass of 119 Number of protons = 50 Number of neutrons = 69 Number of electrons = 48
Calculating Atomic Mass of Molecules When you add the atomic mass of two
particles together, you get the atomic mass of the molecule.
You can have more than one of any atom, so you need to multiply the mass times that number.
Ex. CO is Carbon Monoxide Carbon has an atomic mass of 12 Oxygen has a mass of 16 The total mass for the molecule is
12+16= 28g
What about More than One of an atom? If there are more than one atom of a given
kind, multiply that subscript number by the atoms mass.
Then add the total of all the atoms.
Examples: H2O Multiply the hydrogen by 2 then add it
to the oxygen. (Hx2)+O= (1x2)+16=18g
C6H12O6 (Cx6)+(Hx12)+(Ox6)= (12x6)+(1x12)+(16x6) =180g
The Mole: more than just a furry little creature… It is a unit of measure,
since atoms are very, very, very small a better way to count atoms so the unit is the mole
The mole is equal to 6.022x1023 also called Avogadro’s number
1 mole of a element = atomic mass of that element
Grams to molesTake the given number of grams and multiply it by 1 mole over the atomic mass.
Example: How many moles is contained in a 72g sample of magnesium?
72 g of Mg x 3 mol 1 mol =24 g
Moles to gramsTake the given number of grams and multiply it by atomic mass over 1 mole
Example: How many grams are there in a 1.5 mole sample of sulfur?
1.5 mol x = 48 grams32 g 1 mol
Atoms to moles & moles to atoms To calculate the number of moles in a
amount of atoms, divide by Avogadro's number
To calculate the number of atoms in a sample, first convert to moles, then multiply by Avogadro's number
Island of Instability…There are 92 naturally occurring elements
But scientists can make elements in the lab, the current “prize” is to make & stabilize element 114…