Chemistry and the Properties of Life

Properties of Life Cellular Organization Homeostasis Metabolism Responsiveness Reproduction Heredity Growth Movement

Cellular Organization All living things are made of cells.

Homeostasis All organisms maintain stable internal conditions that are different than the surrounding environment.

Metabolism All organisms require energy and produce waste products. Food energy is used to maintain internal order and to grow.

Responsiveness All organisms respond to internal and external stimuli.

Reproduction All organisms are capable of reproduction

Heredity Any organism originates from an organism or organisms of the same species. Living things do not spring into life randomly.

Growth All organisms grow and develop through definite stages Beginning, growth, maturity, decline, and death.

Movement All organisms are capable of self-generated movement at some scale and at some stage of their life cycle.

Chemistry Basics All living things are made of atoms Atoms: the smallest particle into which an element can be divided and still be the same substance

Subatomic Particles Protons: positively charged particles located in the nucleus Neutrons: particles without a charge that are located in the nucleus Electrons: negatively charged particles that are located in the electron cloud

Electron Configuration The location within the electron cloud where the electrons are most likely to be found 1st shell holds maximum of 2 electrons All other shells hold a maximum of 8 electrons

Atomic Structure

Elements on the Periodic Table

Atomic Weight The total number of protons and neutrons added together

Periodic Table

How to find numbers of… Number of protons = Atomic Number Number of electrons = Atomic Number Number of neutrons = Atomic Weight – Atomic Number *Round atomic weight to the nearest whole number before subtracting

Outer Shells The number of outer shells an atom has in its electron cloud can be determined by the row the element is placed on the periodic table

Valence Electrons The number of valance electrons an atom has can be determined by which column the element is placed into on the periodic table

Shells and Valances

Bonding to Make Compounds

Molecule A group of atoms held together by covalent bonds

Compound A substance composed of two or more elements that are combined

Valance Electrons The number of electrons in the outer shell. Used for bonding

Octet Rule When bonding, each atom wants to have a full outer shell (8 valance electrons) ***Exception is Hydrogen, which can only hold two electrons in its outer shell

Types of Bonding Covalent Bonding Ionic Bonding Hydrogen Bonding

Covalent Bonds When bonds form between atoms by sharing valence electrons

Ionic Bonds When bonds form between atoms by either gaining or losing electrons Results in the compound having either a positive or negative charge

Ions When an atom has an electrical charge it is called an ion If an atom gains an electron it has a negative charge If an atom loses an electron it has a positive charge

Polarity When shared electrons are attracted to one atom more strongly than another, so it has a slightly negative charge The other atom that the electrons are less strongly attracted to has a slightly positive charge

Solubility Like dissolves like Substances with like charges will dissolve one another, but substances with opposite charges will not

Hydrogen Bond When a hydrogen atom has a partial positive charge that is very strong it attracts to the negative pole of specific other molecules Oxygen, Nitrogen, Fluorine This is a very strong bond, but not as strong as a covalent bond.