molecular formula showing the number of atoms of each element (H2O)
The atoms of a molecule are held together by forces of attraction called molecular bonds.
True or False?
False. Molecules are held together by CHEMICAL bonds.
What is the outermost shell of a molecule called?
valence shell.
The likelihood that an atom will
form a chemical bond with another atom depends on the number of electrons in its outermost shell, also called the valence shell.
True of False?
True
When an atom loses or gains a valence electron what is formed?
An Ion.
Positively and negatively charged ions are attracted to one another.
Positively charged ions that have given up one or more electrons (they are electron donors).
Cations
Negatively charged ions that have picked up one or more electrons that another atom has lost (they are electron acceptors).
Anions
Ionic Bond Formation
What type of bond is formed bonds by the atoms of molecules sharing one, two, or three pairs of their
valence electrons?
Covalent Bonds. They are the strongest in the body and can be single, double or triple.
What is a nonpolar covalent bond?
In a nonpolar covalent bond, atoms share the electrons equally; one atom does not attract the shared electrons more strongly than the other atom
Define a polar covalent bond.
Unequal sharing of electrons between atoms. In a water molecule, oxygen attracts the hydrogen electrons more strongly
Oxygen has greater electronegativity as indicated by the negative Greek delta sign.
Hydrogen Bonds are stronger than covalent bonds.
True or False?
False.
Hydrogen Bonds are Approximately 5% as strong as covalent bonds
Are weak intermolecular bonds; they serve as links between molecules.
Help determine three-dimensional shape
Gives water considerable cohesion
Define Chemical Reaction
New bonds form and/or old bonds are broken.
Metabolism is “the sum of all the chemical reactions in the body.”
Define Energy.
the capacity to do work
Define Potential Energy.
Energy stored by matter due to its position.
Define Kinetic Energy.
The energy associated with matter in motion.
Define an exergonic reaction.
reaction is one in which the bond being broken has more energy than the one formed so that extra energy is released,usually as heat (occurs during catabolism of food molecules). (Breaking Down Reactions that release Energy)
Define an endergonic reaction.
reaction is just the opposite and thus requires
that energy be added, usually from a molecule called ATP, to form a bond, as in bonding amino acid molecules together to form proteins. (Building Reactions that require the input of Energy)
What factors influence the possibility of having a chemical reaction?
Amount of reactants
Temp.
Presence of a Catalyst.
What does a Catalyst do?
A catalyst is a chemical compound that speeds up chemical reactions by lowering the activation energy needed for a reaction to occur. (Enzymes)
•A catalyst does not alter the difference in
potential energy between the reactants and products. It only lowers the amount of energy needed to get the reaction started.
–A catalyst helps to properly
orient the colliding particles of matter so that a reaction can occur at a lower collision speed.
–The catalyst itself is unchanged at the end of the reaction; it is often re-used many times.
Synthesis reactions are ?
Anabolism
(Endergonic)
Decomposition reactions are ?
Catabolism
(Exergonic)
Organic compounds usually lack
carbon and are simple molecules; whereas inorganic compounds always contain carbon and hydrogen, usually contain oxygen, and always have covalent bonds.
True or false?
False.
The opposite it is true.
Water
Is the most important and abundant inorganic compound in all living systems.
Water’s most important property is polarity, the uneven sharing of valence electrons
