Chapter 2 Chem. Foundation of Life

BIO 101

Atomic Structure - What is the outermost electron shell of an atom called?

Valence shell

Atomic Structure - What is the Octet Rule?

Atoms are most stable when their valence shell contain 8 electrons

Atomic Structure - What are the charges and locations of the three subatomic particles?

Protons (positive, in nucleus), Neutron (neutral, in nucleus), Electrons (negative, orbiting in shell)

Atomic Structure - What is the atomic number?

The number of protons in an atom (dictates element post in periodic table)

Atomic Structure - What are isotopes?

Atoms of the same element that vary in the number of neutrons in their nuclei

Atomic Structure - What is the smallest unit of matter that retains the chemical properties of an element?

Atom

Atomic Structure - If Xenon has an atomic number of 54 and and atomic mass of 108, how many neutrons does it have?

54 Neutrons (Mass 108 - Atomic Number 54 = 54 Neutrons)

What is the electron configuration for Potassium (atomic #19)?

Shells 1,2, and 3 are full, and shell 4 has 1 electron (Sequence: 2, 8, 8, 1)

Chemical Bonds - How do ionic bonds form?

An electron is transferred from one atom to another, forming ions that are electrostatically attracted

Chemical Bonds - How doe covalent bonds form?

Electrons are shared between atoms to complete their valence shells

Chemical Bonds - What is a Polar Covalent bond?

A bon where electrons are shared unequally due to difference in electronegativity

Chemical Bonds - What is Electronegativity?

The ability of an atom to attract electrons, increasing the electron density around one part of a molecule (creating partial charges)

Chemical Bonds - What type of bond represents a weak chemical bond?

Hydrogen bond

Chemical Bonds - What type of bond reperesents a weak chemical bond?

Hydrogen bond

Chemical Bonds - What is formed when an atom gains or loses electrons?

An ion

Water Properties - What is the chemical formula of water?

H2O

Water Properties - In a water molecule, which atom has a partial positive charge and which has a partial negative charge?

Hydrogens have a partial positive charge; Oxygen has a partial negative charge

Water Properties - What two properties allow water to be transported from plant roots to leaves?

Cohesion and Adhesion

Water Properties - Why is water a good solvent that facilitates chemical reactions?

Because it is polar, it can dissolve many substances, allowing them to move freely an react

Water Properties - What is the most abundant chemical in the Earth’s atmosphere?

Nitrogen (followed by Oxygen)

Water Properties - What determines whether a molecule is hydrophilic or hydrophobic?

Hydrophilic molecules interact with water (polar), but Hydrophobic molecules do not (nonpolar)

Acids, Bases,& pH - What does pH measure?

The concentration of Hydrogen ions in a solution

Acids, Bases,& pH - When acids are added to a solution hat happens to the pH?

It decreases and becomes more acidic

Acids, Bases,& pH - What do we call a molecule that binds up excess hydrogen ions in solution?

A Base/Basic

Acids, Bases,& pH - A Solution with a pH of 3 is considered…

Acidic/Acid

Acids, Bases,& pH - A Solution with a pH of 12 is considered…

Basic/Base

Carbon & Organic Molecules - What defines an organic compound?

It contains both carbon and hydrogen atoms

Carbon & Organic Molecules - Is water (H2O) an organic or inorganic molecule?

Inorganic (It does not contain carbon)

Carbon & Organic Molecules - How many other atoms can one carbon atom bond with?

Four

Carbon & Organic Molecules - What are the four main types of biomolecules in cells?

Lipids, Carbohydrates (sugars), Proteins, and Nucleic Acids (All are organic compounds)