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5.2 The Structure of the Atom

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Presentation on theme: "5.2 The Structure of the Atom"— Presentation transcript:

1 5.2 The Structure of the Atom

2 The Atom Protons (p+) Electrons (e-) Neutrons (no)
The atom is made up of three subatomic particles: Protons (p+) Electrons (e-) Neutrons (no)

3 The protons and neutrons are found in the nucleus at the centre of the atom.
The electrons are found “orbiting” around the nucleus in specific energy levels.

4 The Subatomic Particles
Location Charge Mass Proton nucleus +1 1 Electrons outer shells -1 Neutrons

5 Standard Atomic Notation
Shows: Atomic number the number of protons in the nucleus of an atom The atomic number identifies the atom as a particular element Mass Number The number of protons and neutrons in an atom

6 Uses a standard symbol to represent the element (ex
Uses a standard symbol to represent the element (ex. H for hydrogen, Li for lithium)

7 The Atom Calculating the Number of Subatomic Particles:
Atomic number = number of protons Mass number = number of protons + number of neutrons Number of neutrons = mass number – atomic number Number of protons = number of electrons (neutral atom)

8 Activity 5-4, p. 189 Read the activity and complete #1-4
NOTE: for number 3, do not use Appendix A, instead use the periodic table on p. 197, the mass number is the number under the symbol, rounded. Ex. zinc 65.4 = 65.

9 Answers to Activity 5-4 1. carbon = C, hydrogen = H, nitrogen = N Rule: use the first letter (capital) of each element 2. a. Calcium = Ca, use the first two letters, first letter only capitalized. b. C cannot be used as it is already used for carbon 3. silver (argentum) = Ag, gold (aurum) = Au, copper (cuprum) = Cu, iron (ferrum) = Fe, mercury (hydrargyrum) = Hg, lead (plumbum) = Pb, tin (stannum) = Sn Identify rules…. 4. Next slide…

10 Name of Element Atomic Number Mass Number 126C Carbon 6 12 6530Zn zinc
Standard Atomic Notation Name of Element Atomic Number Mass Number Number of Electrons Number of Protons Number of Neutrons 126C Carbon 6 12 6530Zn zinc 30 65 35 Sulfur 16 Calcium 40 20 nitrogen 7 14

11 Bohr Rutherford Diagrams
Show the quantities and locations of protons, electrons and neutrons in an atom (used for the 1st 20 elements) Atomic Number = # of protons # of neutrons = Mass Number – Atomic Number # of electrons = # of protons in a neutral atom For an atom of Helium: Atomic # = # of protons = 2 = = 2 # of electrons = # of protons = 2

12 Bohr-Rutherford Diagram for He
helium 2e- # of electrons in 1st orbital (energy level) Max = 2 2p+ 2n° # of protons (p) # of neutrons (n) Nucleus

13 Bohr-Rutherford Diagram for K
Potassium 1e- # of electrons in 4th orbital (energy level) Max = 8 8e- # of electrons in 3rd orbital (energy level) Max = 8 8e- # of electrons in 2nd orbital (energy level) Max = 8 2e- # of electrons in 1st orbital (energy level) Max = 2 19p+ 20n° # of protons (p) # of neutrons (n) Nucleus

14 Isotopes Most atoms of an element have the same number of neutrons
A few will have a different number of neutrons Ex. Most Li atoms have 3 protons and 4 neutrons Mass Number = 7 Some have only 3 neutrons Mass Number = 6 Atoms that have the same number of protons but different numbers of neutrons are called isotopes.


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