1. Basic Chemistry Define: Chemistry & Biochemistry

2. All matter is composed of atoms
Basic Chemistry
Chemistry is the study of matter
Anything that has volume and takes up space
Solid, liquid, and gas
Exists as elements in pure form and in chemical combinations called compounds
Organism
All matter is composed of atoms

3. Each element has its own unique symbol
Basic Chemistry
Atoms
The smallest unit of an element that still retains the properties of an element
Elements
A substance made of only one kind of atom
Cant be broken down into simpler substances by a chemical reaction
Ex: Iron is an element – it consists of only iron atoms
Hydrogen and helium are by far the most abundant elements in the universe. However, iron is the most abundant element (by mass) making up the Earth, and oxygen is the most common element in the Earth's crust.[
Each element has its own unique symbol

4. arranged according to similar properties and atomic number
FACTS:
118 known elements
92 occur in nature
arranged according to similar
properties and atomic number
92 occur naturally
Over 92 were made in a lab
Vertical columns contain elements with similar properties
6 elements found in living things: carbon, hydrogen, oxygen, nitrogen, silicon, phosphorus – make up 98% of living things

5. Elements of Life 96% of living organisms is made of: carbon (C)
hydrogen (H)
oxygen (O)
nitrogen (N)

6. Other Elements
A few other elements make up the remaining 4% of living matter
Table 2.1

7. (a) Nitrogen deficiency (b) Iodine deficiency (Goiter)
Deficiencies
If there is a deficiency of an essential element, disease results
(a) Nitrogen deficiency
(b) Iodine deficiency (Goiter)
Figure 2.3

8. Trace Elements
Trace elements Are required by an organism in only minute quantities
Minerals such as Fe and Zn are trace elements

9. Explain the relationship between an atom and an element.
What are the four major elements that make up living organisms?

10. Compounds
Are substances consisting of two or more elements combined in a fixed ratio
Have characteristics different from those of their elements
Sodium
Chloride
Sodium Chloride +
Figure 2.2

11. Molecule of Glucose

12. Atomic Structure
Atoms of each element are composed of subatomic particles
Nucleus
Protons (p+)
Neutrons (n0)
Outside of nucleus
Electrons (e-) in a cloud, electron shells

13. Carbon has ___ p+ and ___ e-
Identifying Elements
Atoms of various elements differ in their number of subatomic particles C
12.011 6
Atomic Number
= # of p+ and # of e- 6
Carbon has ___ p+ and ___ e- 6
protons (+) = electrons (-)
Atoms are electrically NEUTRAL
Atomic Mass
= # protons + # neutrons 6
Carbon has ___ n0

14. C Atomic number – the number of protons – unique to each element
Electron configuration – placement of electrons in energy levels
2 4 6
Atomic symbol – used to represent both the element and one atom of that element C
Carbon
Mass number – number of protons plus the number of neutrons
12.011 12
Atomic mass – the total mass of the atom – sum of the mass of the protons and neutrons – average mass of all isotopes

15. Identifying Elements Practice
Atomic
number
Mass
number

16. Identifying Elements Practice

17. Identifying Elements Practice

18. Identifying Elements
Isotopes – varieties of an element that have different number of neutrons
Same number of protons, different neutrons
Same ____________, different ____________

19. Other uses Can be used in medicine to treat tumors
Cancerous throat tissue
Figure 2.6

20. Energy Energy Potential energy
Is defined as the capacity to cause change
Potential energy
- Is the energy that matter possesses because of its location or structure
Kinetic Energy
- Is the energy of motion

21. Electrons and Energy The electrons of an atom
Differ in the amounts of potential energy they possess
A ball bouncing down a flight
of stairs provides an analogy
for energy levels of electrons,
because the ball can only rest
on each step, not between
steps.
(a)
Figure 2.7A

22. Energy Levels of Electrons
An atom’s electrons vary in the amount of energy they possess
Electrons further from the nucleus have more energy
Electron’s can absorb energy and become “excited”
Excited electrons gain energy and move to higher energy levels or lose energy and move to lower levels

23. Energy Levels Are represented by electron shells
Third energy level (shell)
Second energy level (shell)
First energy level (shell)
Energy
absorbed
lost
An electron can move from one level to another only if the energy
it gains or loses is exactly equal to the difference in energy between
the two levels. Arrows indicate some of the step-wise changes in
potential energy that are possible.
(b)
Atomic
nucleus
Figure 2.7B

24. Why do elements react?
The number of valance electrons determine the chemical behavior of an element
Atoms seek to have “full” outer most electron shells

25. Covalent Bonds The sharing of a pair of electrons
Results in a molecule
Two or more atoms combine and act as a single particle
Example: H2O (water)
Hydrogen Atom
Oxygen Atom
= WATER MOLECULE 1+ 8+
wants to fill this

26. Multiple Covalent Bonds
Name
(molecular
formula)
Electron-
shell
diagram
Structural
formula
Space-
filling
model
Hydrogen (H2).
Two hydrogen
atoms can form a
single bond.
Oxygen (O2).
Two oxygen atoms
share two pairs of
electrons to form
a double bond. H O
Figure 2.11 A, B
(a)
(b)

27. Compounds & Covalent Bonds
Name
(molecular
formula)
Electron-
shell
diagram
Structural
formula
Space-
filling
model
(c)
Methane (CH4).
Four hydrogen
atoms can satisfy
the valence of
one carbon
atom, forming
methane.
Water (H2O).
Two hydrogen
atoms and one
oxygen atom are
joined by covalent
bonds to produce a
molecule of water.
(d) H O C
Figure 2.11 C, D

28. Covalent Bonding Electronegativity The more electronegative an atom
Is the attraction of a particular kind of atom for the electrons in a covalent bond
The more electronegative an atom
The more strongly it pulls shared electrons toward itself

29. Covalent Bonding In a nonpolar covalent bond
The atoms have similar electronegativities
Share the electron equally

30. Covalent Bonding In a polar covalent bond
The atoms have differing electronegativities
Share the electrons unequally
This results in a
partial negative
charge on the
oxygen and a
partial positive
charge on
the hydrogens.
H2O d– O H d+
Because oxygen (O) is more electronegative than hydrogen (H),
shared electrons are pulled more toward oxygen.
Figure 2.12

31. Ionic Bonds Formed by the transfer of electrons between atoms
Results in ions
an atom that has lost or gained electrons = electric charge
Example: NaCl (table salt)
Chlorine Ion -1 (Anion)
Chlorine Atom
Sodium Atom
Sodium Ion +1 (Cation)
11+
17+

32. Ionic Substances Ionic compounds
Are often called salts, which may form crystals
Figure 2.14
Na+
Cl–

33. Weak Chemical Bonds
Several types of weak chemical bonds are important in living systems
This includes:
hydrogen bonds
Van der Waals interactions
Weak chemical bonds are important because
Reinforce the shapes of large molecules
Help molecules adhere to each other

34. Van der Waals Interactions
Even non-polar molecules can have some positively and negatively charged region briefly and can very weakly bind to another.
Plasma membrane are stabilized by the additive affect of Van der Waals interactions between non-polar fatty acid tails of phospholipids.

35. Hydrogen Bonds
H bonds
The two strands of a DNA molecule are held together tightly by the additive affect of many, many weak Hydrogen Bonds
Forms when a hydrogen atom that is covalently bonded to on electronegative atom is attracted to another electronegative atom
Formed between two partially charged atoms
Weaker than ionic bonds

36. Molecules of Life
Put C, H, O, N together in different ways to build living organisms
What are bodies made of?
carbohydrates
sugars & starches
proteins
fats (lipids)
nucleic acids
DNA, RNA

37. Molecular Shape Determines Function
Determines how biological molecules recognize and respond to one another with specificity
Morphine
Carbon
Hydrogen
Nitrogen
Sulfur
Oxygen
Natural
endorphin
(a) Structures of endorphin and morphine. The boxed portion of the endorphin molecule (left) binds to receptor molecules on target cells in the brain. The boxed portion of the morphine molecule is a close match.
(b) Binding to endorphin receptors. Endorphin receptors on the surface of a brain cell recognize and can bind to both endorphin and morphine.
Endorphin
receptors
Brain cell