Chemistry Review Do you remember anything from science investigations?
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Transcript of Chemistry Review Do you remember anything from science investigations?
Chemistry Review
Do you remember anything from science investigations?
Atomic Structure
Nucleus- center of an atom -contains protons - which are positive -contains neutrons- which are neutral Electrons (which are negative) surround the
nucleus in energy levels 1st energy level = holds 2e 2nd energy level = holds 8e 3rd energy level = holds 18e 4th energy level = holds 32e
Bohr Model of Atom
Periodic Table tidbits
Period table organization – organized by increasing atomic number
Split into metals (left side of stair step line) and nonmetals (right side of stair step line)
Groups – vertical columns (#1-18) Periods – horizontal rows (#1-7)
More Chemistry tidbits Atomic number = number of protons Mass number = # protons + # neutrons #Neutrons = mass number - # protons # protons = # electrons REMEMBER “APE”= ATOMIC NUMBER,
#PROTONS, #ELECTRONS WILL EQUAL EACH OTHER IN A NEUTRAL ATOM
Isotopes (I said isotope you dope!)
Isotopes are different atoms of the same element that contain the same number of protons but different number of neutrons.
Examples Cl-35 vs. Cl-37 17P 17P 18N 20N
Chemical Bonding Remember atoms bond with one another
in order to become stable (need to get 8 electrons in outer ring)
Exception- hydrogen only needs 2 electrons in outer ring to be stable
Bonds are forces of attraction between elements
Involves bonding of valence electrons (electrons in outermost shell)
Lewis Dot Structures
Lewis dot diagrams- display the number of valence electrons (outermost electrons) around the element symbol
Used to show how atoms of different elements bond and form compounds
Hint- use group number to find valence electrons
Electron configurations
Lewis Dot Diagrams
Types of Bonds
Covalent bond – sharing of electrons
-occurs between 2 nonmetals
-types- single (shares 1 e)
double (shares 2 e)
triple (shares 3 e)
*REMEMBER HYDROGEN IS A NONMETAL AND FORMS COVALENT BONDS!!!
Covalent bonds
H2-hydrogen gas-sharing of electrons
Types of Bonds
Ionic bond- one atom gives an electron to another atom (remember it’s the losing and gaining of electrons)
Involves forming ions (have positive and negative charges)
Occurs between a metal and a nonmetal
Bond Diagrams
Covalent bonds-remember they share electrons
Ex. F2
Bond Diagrams
Ionic Bond-
-lose & gain
electrons Ex. NaCl
Ionic bond Lewis dot diagram
NaCl- sodium chloride
Covalent Bond Lewis dot structure
HF-hydrogen fluoride
What is inside the nucleus of an atom?
1. Protons and electrons
2. Electrons and neutrons
3. Protons only
4. Protons and neutrons
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What are the dots in Lewis dot diagrams?1. Number of protons
2. Number of neutrons
3. Number of valence electrons
4. Number of inner shell electrons
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An ionic bond is between 1. 1 metal and 1
nonmetal
2. 2 nonmetals
3. 2 metals
4. None of the above
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A covalent bond is between
1. 2 metals
2. 1 metal and 1 nonmetal
3. 2 nonmetals
4. 3 metals
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How do you find the number of valence electrons to draw for a Lewis dot diagram
1. Look at the atomic number
2. Look at the mass number
3. Look at the number of neutrons
4. Look at the group number
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