Biochemistry-SCH4U Review Flashcards
What are 6 types of atoms that make up 99% of all living organisms.
Oxygen
Carbon
Hydrogen
Nitrogen
Phosphorus
Sulfur
Percentage of human body weight that each atom makes up.
Oxygen-65.0
Carbon-18.5
Hydrogen-9.5
Nitrogen-3.3
Phosphorus-1.0
Sulfur-0.3
Matter Definition
Any substance in the universe that has mass and occupies space.
Matter is composed of what?
Extremely small particles called atoms.
Atoms are what?
The smallest unit of any given element.
Same Basic structure of every Atom
Core nucleus of both protons and neutrons
Orbiting cloud of electrons
Atomic # Meaning
of protons= # of electrons
Mass Number Meaning
Number of Protons + Neutrons
Charges of Subatomic Particles
Protons-Positive Charge
Neutrons-No Charge
Electrons-Negative Charge
Parts of Atoms
Nucleus
Shells
Parts of Nucleus
Protons
Neutrons
Isotopes Meaning
Atoms of the same element that vary in the number of neutrons
Same Number of Protons in Isotopes Result In
All isotopes of an element having the same chemical properties
Chemical Behaviour of Atom determined by what
Its electron configuration
Electron Configuration Meaning
The distribution of electrons in the atom’s electron shells
Chemical behaviour of an atom depends largely on the number of electrons in its
Outermost shell (valence electron/shell)
Atoms with incomplete valence shells are what
Chemically reactive
of electrons outermost electron shell can hold
8 electrons
of electrons first electron shell can hold
2 electrons
Octet rule meaning
Atoms tend to gain, lose, or share electrons so as to have 8 electrons
C would like to
Gain/lose 4 electrons
N would like to
Gain 3 electrons
O would like to
Gain 2 electrons
H would like to
Gain 1 electron
Atoms bond to what
Form compounds
What compounds are made up of
At least 2 different kinds of atoms (e.g., H2O)
Bonds are formed by what
The sharing or transfer of electrons
2 Types of Chemical Bonds
-Ionic Bonds
-Covalent Bonds
Ionic Bonds Occurrence
Occur when one atom donates or gives up one or more electrons
Opposite charges attract to form what?
Ionic bonds
Covalent bonds involve
A sharing of a pair of valence electrons between atoms.
H2 covalent bond type
Single covalent bond
O2 covalent bond type
Double covalent bond
CH4 (Methane) covalent bond type
Four single covalent bonds
H2O (Water) covalent bond type
Two single covalent bonds
Two types of covalent bonds
Polar Covalent
Non-Polar Covalent
Polar Covalent Meaning
Unequal sharing of electrons (E.g. H2O)
Non-Polar Covalent Meaning
Equal sharing of electrons (E.g. H2, O2)
Sharing of electrons determined by what
By the atoms
Sharing of electrons determined by the atoms meaning
Electronegativity
Electronegativity meaning
The measure of the relative abilities of bonding atoms to attract electrons (Pauling Scale)
Increased electronegativity =
Stronger pull of shared electrons
Periodic table contains
Electronegativity values
We can determine the nature of a bond based on
ΔEN (electronegativity difference)
In a non-polar covalent bond, there is relatively
no electronegative difference.
In a non-polar covalent bond,
Electrons are shared equally. E.g., O2 oxygen atoms have the same electronegativity
In a polar covalent bond, there is
an electronegative difference.
In a polar covalent bond,
Electrons are shared unequally. E.g., H2O oxygen atom is more electronegative than the hydrogen atoms
Polar Covalent Analogy
The boy is not equally sharing with anyone else but rather taking all the food for himself.
Non-Polar Covalent Analogy
The children are equally sharing the drink between themselves.
Water is a ________ molecule because
Polar; because oxygen is more electronegative than hydrogen, and therefore electrons are pulled closer to oxygen.
In water, shared electrons
spend more time near the the oxygen nucleus
Shared electrons spend more time near the the oxygen nucleus =
oxygen atom gaining a slightly negative charge and the hydrogen atoms becoming slightly positive
Polar molecules (like water) have what
An unequal distribution of charge
Since water is __________, it can _________ what?
Polar; Attract; Other water molecules
The attraction between water molecules are called what
Hydrogen bonds
Type of Force of Hydrogen Bonds
Weak forces between molecules
Why is water good because of its polarity?
A good solvent
Solvent Meaning
A substance in which a solute dissolves
Solute Meaning
What is being dissolved
Water is great at
Dissolving both ionic (+,-) compounds and polar (partial positively, partial negatively charged molecules) molecules.
Hydrophilic Compounds (love or hate water)
Love water-Interact with it by dissolving in it.
Hydrophobic Compounds (love or hate water)
Hate water-Do not interact with water because they cannot form hydrogen bonds
Example of Hydrophilic Compound
Anions (chloride ions) in salt attracted to + poles of water
Example of Hydrophobic Compound
E.g., Non-polar compounds are insoluble in water
Oil – non-polar compound of carbon and hydrogen
