Chemistry CLS 101for Nursing Students

CHEMICAL BONDS

When atoms combine, we obtain the variety of substances that

surround us.

CHEMICAL BONDS

• Is the force of attraction between any two elements in a compound.

IONIC BONDS• Bond formed due to the gain or loss of

electrons in atoms i.e. due to transfer of electrons between atoms.

• When an atom loses an electron it is a POSITIVE charge.

• When an atom gains an electron it is a NEGATIVE charge

• These newly charged atoms are now called IONS– Example: NaCl (SALT)

Na (2,8,1) Na+ (2,8) + e- Cl (2,8,7) + e- Cl- (2,8,8) Na+ + Cl- NaCl

Ions are the charged particles

Ionic Bond

Chemical Reaction

A chemical reaction is a process during which one or more components are transformed into new substances.

IONIC BONDS

• The ionic bond is the force of attraction that binds together unlike charged ions to form a chemical compound.

Electronegativity

Ionic bonds are formed due to differences in the tendency of atoms to attract electrons towards them.

The tendency to attract electrons is known as Electronegativity.

COVALENT BONDS

SHARING IS CARING!

Electrons are shared between two atoms. Each covalent bond between atoms involves two electrons. Thus if the atoms are similar in negativity then the electrons will be shared

Covalent Bond When two electron pairs are shared,

it is double bond.

Example:

C2F4

Non-Polar Covalent Bond

• Equal distribution of charge around a central atom.

• Molecule has a symmetrical shape.

Non-Polar Covalent Bond

Example: The hydrogen atoms are sharing two electrons

between themselves. Such a shared pair of electrons makes up a single bond.

HB+ HA HBHA

Polar Covalent bond

• Electrons are shared, but not equally.

• Some atoms have a stronger pull for the electrons.

• Molecule not symmetrical in shape (unbalanced).

• The atoms share electrons but the electrons spend more of their time around on atom versus the others in the compound. This type of bond occurs when the atoms involved differ greatly in electronegativity. The most familiar example is water. Oxygen is much more electronegative than hydrogen, and so the electrons involved in bonding the water molecule spend more time there.

Polar Covalent bond

Co-ordinate (Dative Bonds)

A dipolar bond, also known as coordinate covalent bond, dative bond, or semipolar bond, is a description of covalent bonding between two atoms in which both electrons shared in the bond come from the same atom.

Co-ordinate (Dative Bonds)

E.g. Ammonium ion

Metallic Bond

• In some metals, valence electrons are shared, free to move about.

• Metal—metal.• Metals conduct electricity easily.• Not all metals exhibit metallic bonding.• E.g. Zinc Metal

Is the attractive interaction of a hydrogen atom with an electronegative atom, such as nitrogen, oxygen, that comes from another molecule or chemical group. The hydrogen must be covalently bonded to another electronegative atom to create the bond.

Hydrogen Bonds