Presentation on theme: "OF PROTONS, NEUTRONS AND ELECTRONS IN AN ATOM"— Presentation transcript:
1 OF PROTONS, NEUTRONS AND ELECTRONS IN AN ATOM DETERMINE THE NUMBEROF PROTONS, NEUTRONS AND ELECTRONS IN AN ATOM
2 Counting the Pieces Atomic Number = number of protons # of protons determines kind of atom.the same as the number of electrons in the neutral atom.
3 Counting the Pieces Mass Number = the number of protons + neutrons. All the things with mass.NOT on the periodic table
4 IsotopesAtoms of the same element can have different numbers of neutrons.different mass numbers.called isotopes.
5 Writing Isotopes Two ways: Hyphen notation Name of element – mass numberEx:carbon- 12carbon -14uranium-235
6 Nuclear Symbol Notation Contain the symbol of the element, the mass number and the atomic number.MassnumberXAtomicnumber
7 Na Symbols 24 11 Find the number of protons number of neutrons number of electronsAtomic numberMass NumberName24Na11
8 Na Symbols 24 11 Find the number of protons = 11 number of neutrons = 13number of electrons = 11Atomic number = 11Mass Number = 24Name = sodium – 2424Na11
9 Br Symbols 80 35 Find the number of protons number of neutrons number of electronsAtomic numberMass NumberName80Br35
10 Br Symbols 80 35 Find the number of protons = 35 number of neutrons = 45number of electrons = 35Atomic number = 35Mass Number = 80Name = bromine - 8080Br35
11 Symbolsif an element has an atomic number of 34 and a mass number of 78 what is thenumber of protonsnumber of neutronsnumber of electronssymbolName
12 ANSWERSif an element has an atomic number of 34 and a mass number of 78 what is thenumber of protons = 34number of neutrons = 44number of electrons = 34Name = selenium – 7878Se34
13 Symbols if an element has 91 protons and 140 neutrons what is the Atomic numberMass numbernumber of electronsNamesymbol
14 ANSWERS if an element has 91 protons and 140 neutrons what is the Atomic number = 91Mass number = 140number of electrons = 91Name = Protactinium - 140Pa14091
15 Average Atomic MassA weighted average of all naturally occuring isotopes of an element.There is a formula used to calculate average atomic mass:= (mass of isotope 1) (% abundance/100)(mass of isotope 2) (%abundance/100)+...________________________________
16 Unit for Atomic Mass The atomic mass unit (amu) amu definition - one twelfth the mass of a carbon-12 atom.Each isotope has its own atomic mass relative to the carbon-12 atom
17 Atomic MassYou try…Calculate the atomic mass of copper if copper has two isotopes. 69.1% has a mass of amu and 30.9% has a mass of amu.