Chemistry Unit 1 Electronegativity and Polarity PDF

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Practice material on electronegativity and polarity. There are fill in the blanks....

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SCH3U- Unit 1

Name:________________________

Electronegativity and Polarity Remember:    

Electronegativity is the ability of an ____________________ atom, when bonded, to ___________________ bonding electrons to itself this determines how electrons are _________________ in a chemical bond It is measured using a scale (_________________) An element with a high electronegativity is _________________ at pulling a pair of electrons toward itself, whereas an element with a __________ electronegativity is not. _________________ has the highest value on the periodic table, while _______________ the lowest.

Determining if a Compound is Ionic or Molecular 

 

We can determine if a bond is ionic or covalent/molecular by use of the _________________________ in the electronegativity (__________) values of the two elements involved. Whether the difference is positive or negative does not matter-only the _______________________ of the difference, so the equation uses an absolute value: NaCl ΔEN = │ │

Non polar Covalent Bond   

When electrons are __________________ between 2 atoms, a __________________ bond is formed. If the atoms are _________________, e.g. Cl2, the electrons are shared __________________ (non-polar) ΔEN =

Polar Covalent Bond   

If the electrons are shared between 2 _________________ atoms, the sharing is ____________________ The bonding electrons spend ______________ _____________ near the more electronegative atom ΔEN =

SCH3U- Unit 1

Name:________________________



This is not a complete transfer of an electron from hydrogen to fluorine; it is merely a drifting of electrons toward fluorine When a charge separation of this type is present, the molecule possesses an electric dipole, so called “_______________________” and the bond is called a ________________________________________________



Example: Water (H2O)



∆EN = 1.24 (which is between 0.4 and 1.7)

Oxygen = a slightly negative charge Hydrogen = a slightly positive charge



Since the hydrogen does not completely transfer its electron to the oxygen, the their respective charges are indicated as ________________ (the indication of partial positive charge) and _______________ (indication of partial Negative charge).

Electronegativity Differences  The absolute value of the difference in electronegativities of two bonded atoms provides a measure of polarity of a bond.  The greater the difference, the more polar the bond.

SCH3U- Unit 1

Name:________________________

Identify each compounds as ionic, polar- covalent or non-polar H-CI,

C-Cl

MgF2,

H2O,

NH3,

NaCl,

OH,

H2

Polar Molecules 

Not all molecules with polar bonds are _________________ molecules

The overall polarity of a molecule depends on a combination of: 

-

 To predict the polarity of the molecule: i.

Determine if there are _________________ bonds using _____________________ value

ii.

If there are polar bonds, establish the _____________________ of the dipoles.

(A _____________ exists when two _____________ charges are separated by a short distance)

( +   -) iii.

identify the _________________ of the molecule  if the dipoles _________________ due to the shape of the molecule then the compound is ______________________________________  if the dipoles ______________________________ due to the shape of the molecule then the compound is _____________________

Polarity of molecule Chemical formula

Lewis diagram (polar/non-polar)

CH4 methane

CO2

H 2O...