Biol 1201: C2

Chemical Context of Life

What is a compound?

Made of atoms joined by bonds.

What does the number of protons determine?

An atoms identity(Ex: Oxygen atomic number of 8)

What does electron distribution determine?

An atoms ability to form bonds.

What is matter?

Anything that takes up space and has mass

What is matter made of?

Elements

What is a compound?

A substance consisting of two or more elements in a fixed ration

Compound Vs. Element?

A compound has different characteristics than its element

What elements take up the most of human body

1. Oxygen, 2. Carbon 3. Hydrogen, 4. Nitrogen

What is an atom?

The smallest unit of matter that still retains the properties of an element.

What are atoms composed of?

Protons, Neutrons, Electrons

What forms the atomic nucleus?

Protons and neutrons

What is measured in daltons?

Proton and Neutron mass(nearly identical.

What is atomic number?

number of protons

What is mass number?

number of protons and neutrons

What is atomic mass?

Atoms total mass(can be approximated by mass number)

What is an isotope?

same number of protons but differing number of neutrons

what do radioactive isotopes do?

decay spontaneously, giving of particles and energy.

What are valence electrons?

those in the outermost shell aka valence shell.

What elements are chemically inert?

those with a full valence shell

What happens with atoms with incomplete valence shells?

Sharing or transferring of valence electrons, resulting in chemical bonds.

What is a covalent bond?

Sharing a pair of valence electrons by two atoms(count as a part of each atoms valence shell)

What is a molecule?

Consists of two or more atoms held together by covalent bonds

What is a compound?

A combination of two or more different compounds

what is electronegativity?

an atoms attraction for the electrons in a covalent bond(more electronegativity= stronger pull of electrons)

When do atoms share electrons equally?

nonpolar covalent bond

When DON’T atoms share electrons equally?

polar covalent bonds

What does unequal sharing of electrons cause?

Partial positive or negative charge for each atom or molecule

What is an ionic bond?

When an atom strips electrons from their bonding partners(attraction between cation and anion), as a result both atoms have charges(cation or anion)

what do ionic bonds form?

ionic compounds or salts

what is a hydrogen bond?

when a hydrogen atom covalently bonded to one electronegative atom is also attracted to another electronegative atom.