Chp 2 Chm context of life

Question 0

Compare and contrast Elements, Atoms, Molecules, Compounds.

Answer 0

Elements - is a substance tht cannot be broken down to other substances by chemical rxn.
Atoms - Are the smallest unit of matter tht retains the properties of an element.
Molecules - two or more elements held together by a covalent bond
Compound - is 2 or more different elements combined ion a fixed ratio.

Question 1

From the periodic table be able to determine
Atomic # # of protons
Mass # # of electrons
Atomic Weight # of nuetrons

Answer 1

Atomic # - # of protons which indicates the atom Carbon 6 protons
Mass # - is protons + neutrons
Atomic weight - the decimal at the bottom
# of protons - Atomic #
# of electrons - equal to protons if the charge is neutral
# of Nuetrons - atomic weight - protons

Question 2

Compare and contrast electron shell and valence electrons.

Answer 2

Electron shells - electrons are found in different electron shell.
Valence Electrons - are the electrons in the outer most shell. AKA Valence shell

Question 3

First define isotopes. Then,

Compare and contrast Stable and radio active isotopes

Answer 3

Isotope - The different atomic forms of the same element (isotopes behave identically in chemical rxn)
Stable isotopes - means tht their nuclei does not have a tendency to lose subatomic particle, a process called decay. ex. carbon 12/ 13
Radioactive isotopes - means tht the nucleus decays spontaneously, giving off particles and energy. ex. Carbon 14

Question 4

Compare and cont. Neutral atoms and Ions.

Answer 4

Neutral atoms - are atoms that are not charged. in another sense neutral.
Ions - can be broken down into two categories cations + charged atoms or anions - charged

Question 5

C & C Covalent and Ionic bonds

Answer 5

Covalent bonds - a sharing of a pair of valence electrons

Ionic Bonds - Any two ions with the opposite charge can form an ionic bond

Question 6

C & C polar and nonpolar covalent bond.

Answer 6

Nonpolar - refers to the electronegativity of each atom in the bond but nonpolar specifically refers to an equal share of electronegativity between the atoms. (standstillzz, non moving) CH4 C2H4 etc…
Polar - is when two atoms are bonded together with different electronegativity. Thus the electrons are not shared equally giving one atom more - charge with the other being more +.

Question 7

C & C Form and function of biological structures.

Answer 7

Shape determines function.

Question 8

Define valence shell

Answer 8

Valence shell is the outer most electron shell in an atom

Question 9

Define the octet rule

Answer 9

The octet rule is tht no shell after the first may hav more than 8 electrons interacting with it.

Question 10

how can the valence shells and octet rule affect covalent bonds.
give ex of C and O separately.

Answer 10

Carbon has a total of 6 electron giving it 4 valence electrons. Thus meaning Carbon wants 4 more valence electron to complete the octet rule of having 8 electrons in its most outer shell. ex CH4
Oxygen has 8 electrons giving it 6 valence electrons. meaning its willing to take two more. thus bonding with H to make H2O.

Question 11

Why is hydrogen so reative

Answer 11

Hydrogen wants to be positive if it can be but it only has one electron making it very reactive to electronegative atoms.

Question 12

Name each chemical symbol.

N O C H P S

Answer 12

Nitrogen, Oxygen, Carbon, Hydrogen, Phosphorus, Sulfur

Question 13

What are hydrogen bonds and what type of compounds make them up?

Answer 13

H-Bonds are weak chemical bonds but are attracted to the electronegative atoms of Nitrogen Oxygen and Florine. ex H2O, and DNA