7th Grade-Ch. 1 Sec. 4 Covalent BondsPresentation Transcript
Ch. 1 Sec. 4 s
usually form between 2 nonmetals
C 2 H 6
neutral group of atoms joined by covalent bonds
CH 4 Carbon has 4 electrons in its outer shell. It needs 4 more electrons. Hydrogen needs 1.
covalent bond in which valence electrons are shared equally
Covalent bond in which electrons
are shared unequally
Water molecules are polar
Polar bond Unequal sharing of electrons
Unequal sharing of an electron in a polar-covalent bond between 2 atoms is like 2 neighbors buying and sharing one snowblower.
But one neighbor has a much
longer driveway than the other.
After a snowstorm, the snowblower will spend much more of its time at the house with the longer driveway than the other.
F, O, Cl have long driveways.
Be Nice, Clear Your Ice
Fluorine forms a nonpolar bond with another fluorine atom. In hydrogen fluoride, fluorine attracts electrons more strongly than hydrogen does, so the bond formed is polar.
2 pairs of electrons are shared
3 pairs of electrons are shared
molecules having covalently bonded atoms
H 2 O
Properties of molecular compounds CH 3 CH 2 OH
& boiling point
2. Poor conductors of electricity
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What holds covalently bonded atoms together?
The force that holds atoms together in a covalent bond is the attraction of each atom’s nucleus for the shared pair of electrons .
How does unequal sharing of electrons occur, and how does it affect molecules?
Atoms of some elements pull more strongly on shared electrons than do atoms of other elements. As a result, the electrons are pulled more toward one atom, causing the bonded atoms to have slight electrical charges .
What are the properties of molecular compounds?
Molecular compounds generally have lower melting points and boiling points , and they do not conduct electricity when dissolved in water.