Put HW into the bin
Download
1 / 28

Put HW into the bin Quiz on Chem vocabulary Review HW-notes! - PowerPoint PPT Presentation


  • 86 Views
  • Uploaded on

Put HW into the bin Quiz on Chem vocabulary Review HW-notes!. Chemistry Review. You need to remember some basic things. The Atom. Smallest possible unit that maintains properties of the element Made of: Protons – positively charged particles, define the element , atomic number

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Put HW into the bin Quiz on Chem vocabulary Review HW-notes!' - noelani-jeremiah


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript


Chemistry review

Chemistry Review

You need to remember some basic things


The atom
The Atom

  • Smallest possible unit that maintains properties of the element

  • Made of:

    • Protons – positively charged particles, define the element, atomic number

    • Neutrons- neutral particles, isotopes

      • Together form the atomic nucleus

    • Electrons- negatively charged particles, Bonding

      • Fly around the nucleus

  • Each element has a unique number of protons (atomic number)



Electron orbitals shells
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”


Electron shells
Electron Shells

  • The innermost shell of orbitals is filled first

  • Electrons are distributed to each orbital in a shell before filling each orbital

  • The outermost shell is called the valence shell


Using the periodic table
Using the Periodic Table

  • Ignore 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


Ions

  • Aka charged atoms

  • + ions occur when there are more protons than electrons

  • - ions occur when there are more electrons than protons

  • Atoms can gain and lose electrons


Lewis structures
Lewis Structures

  • Only show the outer most shell electrons or the VALENCE electrons

(only showing the valence electrons)


Draw lewis model
Draw Lewis model:

  • Oxygen

  • Carbon

  • Hydrogen



Filling valence shells
Filling Valence Shells

  • Generally chemical reactions occur that fill valence electron shells

  • Either by gaining/losing electrons

    OR

  • By sharing electrons with other atoms


6a covalent bond
6a. Covalent Bond

  • Sharing of electrons between two atoms

  • A single bond consists of 2 shared electrons, which occupy the valence shell of both atoms

    • Double bond = 4 electrons

    • Triple bond = 6 electrons


Guidelines of bonding
Guidelines of Bonding

  • 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


The column can be used to figure out how many bonds an atom will normally form! This is DIFFERENT than the valence number!

4 3 2 1 0


Lewis structures for molecules
Lewis Structures for molecules will normally form! This is DIFFERENT than the valence number!

  • A line represents 2 electrons, usually shared in a covalent bond

  • Dots represent electrons that are held by only one atom (lone pairs)

  • Only valence electrons are shown

  • Each atom should have a total of 8 electrons (except H and He which hold 2)


6b polar vs non polar covalent bonds
6b.Polar vs. Non-Polar Covalent Bonds will normally form! This is DIFFERENT than the valence number!

Nonpolar

Polar

  • Electrons shared equally

  • Both atoms have similar electronegativity (affinity for electrons)

  • Neither atom ends up with any charge

  • Electrons not shared equally

  • 1 atom is more electronegative (typically O, F, N, & Cl )

  • Electronegative atom ends up with a partial – charge since they often “hog” the electron

  • Other atom ends up with a partial + charge as they have the electron less.


All atoms attract electrons to themselves differently. This is measured by a number called an atom’s ELECTRONEGATIVITY (EN). The HIGHER this number is, the more strongly the atom pulls electrons toward itself.


Non-Polar is measured by a number called an atom’s ELECTRONEGATIVITY (EN). The HIGHER this number is, the more strongly the atom pulls electrons toward itself.

Polar


10 ion formation
10. Ion Formation is measured by a number called an atom’s ELECTRONEGATIVITY (EN). The HIGHER this number is, the more strongly the atom pulls electrons toward itself.

  • Some atoms more easily give up e- (1st and 2nd columns) to get a full valence shell

  • They commonly form bonds with atoms in the 6th & 7th column (respectively) since they need 1 or 2 e-

  • This is 1 way to form ions


  • There other 2 ways to turn an atom into an ion. is measured by a number called an atom’s ELECTRONEGATIVITY (EN). The HIGHER this number is, the more strongly the atom pulls electrons toward itself.

    • Light, e.g. photoelectric effect: where the energy of the incident photon kicks the electron out of its orbit. EX: PHOTOSYNTHESIS

    • Heat: where the kinetic energy of atom and electron vibrations is so large that the electron vibrates away from the atom and does not return.


6c ionic bonding
6c. Ionic Bonding is measured by a number called an atom’s ELECTRONEGATIVITY (EN). The HIGHER this number is, the more strongly the atom pulls electrons toward itself.

  • Opposites attract!

  • Significantly weaker than a covalent bond

  • Can also occur between ionic molecules


11 intermolecular bonds
11. Intermolecular Bonds is measured by a number called an atom’s ELECTRONEGATIVITY (EN). The HIGHER this number is, the more strongly the atom pulls electrons toward itself.

  • Between 2 different molecules (think interstate highway is between 2 different states)

  • I.e. hydrogen bonds in water

  • Much weaker than intramolecular bonds

  • aka intermolecular forces, attractions


Hydrogen bonds
Hydrogen Bonds is measured by a number called an atom’s ELECTRONEGATIVITY (EN). The HIGHER this number is, the more strongly the atom pulls electrons toward itself.

  • Weak attraction between the partial charges of polar covalently bonded molecules

  • In water, between O and H

Means partial


IV. Some Final Key Points… is measured by a number called an atom’s ELECTRONEGATIVITY (EN). The HIGHER this number is, the more strongly the atom pulls electrons toward itself.

A. Molecules are 3-dimensional and have a variety of shapes.

  • 1. The shape of molecules is very important because the ability of molecules to bind with one another is the basis of most functions in our bodies!


ad