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You need to remember some basic things

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Presentation on theme: "You need to remember some basic things"— Presentation transcript:

1 You need to remember some basic things
Chemistry Review You need to remember some basic things

2 The Atom Smallest possible unit that maintains properties of the element Made of: Protons – positively charged particles Neutrons- neutral particles Together form the atomic nucleus Electrons- negatively charged particles Each element has a unique number of protons (atomic number)

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4 Electron Orbitals/Shells
Electrons are found in characteristic areas around the nucleus, called an orbital Each one represents a different energy level Simplifying things, orbitals are grouped into “shells”

5 Electron Shells The innermost shell is filled first
The outermost shell is called the valence shell

6 The first shell has only 1 orbital, so it can hold only 2 electrons
Electron Shells Con. The first shell has only 1 orbital, so it can hold only 2 electrons

7 Represents 1 Orbital. Each orbital gets 1 electron before any orbital in the shell gets a 2nd
The 2nd/3rd Shell Consists of 4 orbitals, so each shell can hold 8 electrons

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9 Draw on your Whiteboard
A neutral boron atom (for the nucleus you can just write B) A neutral fluorine atom

10 Using the Periodic Table
Ignore the D block (the metals) The row tells you the # of shells the atom should have The column tells you the # of valence electrons a neutral atom should have in its valence shell

11 Please add these to your table!

12 Practice using the “short cuts” Draw
A neutral magnesium atom A neutral phosphorus atom

13 Ions: Atomic Charge Charged atoms + ions = more protons than electrons
- ions = more electrons than protons

14 Draw the ions on your Whiteboard
Na+ Si2-

15 Filling Valence Shells
Generally chemical reactions occur that fill valence electron shells Either by gaining/losing electrons OR By sharing electrons with other atoms

16 Lewis Structures Atoms almost always will end up with 8 electrons in their valence shell (may be lone pairs or shared electrons)** So an atom that normally has 6 valence electrons needs to get 2 more from bonding (only showing the valence electrons)

17 The column can be used to figure out how many bonds an atom will normally form


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