Basic Chemistry Vocabulary

Standard Biology

Zito/Farrell

SY 2009-2010

Atom

• the smallest component of an element having the chemical properties of the element

• made up of a specific arrangement of protons, neutrons, and electrons

Nucleus

• positively charged, dense center of an atom

• contains the protons and the neutrons

Proton

• a particle of an atom with a positive charge of +1 and a mass of 1 unit

• always found in the nucleus of the atom

• An atom of a specific element ALWAYS has the same number of protons.

• If you change the number of protons, you make a DIFFERENT element.

Neutron

• a particle of an atom with a neutral charge (charge of 0) and a mass of 1 unit

• always found in the nucleus of the atom

• An atom can have different numbers of neutrons.

• If you change the number of neutrons, you make a heavier or lighter ISOTOPE of the SAME element.

Electron

• a particle of an atom with a negative charge of -1 and a mass of 0 units

• always outside of the nucleus of the atom

• Electrons live in layers called clouds or orbitals.

• An atom of an element can have different numbers of electrons.

• (more on the next slide)

Electrons – ion formation

• Atoms with the SAME number of protons and electrons are called stable atoms, or just plain old atoms.

• An atom that loses or gains electrons is called an ION.

• Losing electrons makes a positive ion (cation)

• Gaining electrons makes a negative ion (anion)

Molecule

• One or more atoms bonded together

• Each molecule that exists has a certain number of atoms, bonded together in a specific arrangement

Molecule Examples

• Oxygen is O2 and

• looks like this.

• Ex: Glucose is always

• C6H12O6 and looks

• like this:

Compound

• Some molecules are compounds, some are not.

• A compound has at least two kinds of atoms.

• Sugar has C, H, & O. it is a compound.

• Oxygen only has O atoms. It’s not a compound. (But it is still a molecule.)

Bonds Between atoms 1

• Electrons are the part of the atom involved in bonding.

• Sometimes one atom totally gives up an electron and another one takes it. This is Ionic Bonding (because ions are made).

Bonds Between atoms 2

• Electrons are the part of the atom involved in bonding.

• Sometimes two atoms share an electron. This makes a COVALENT bond (because they are CO-operating).

Physical Changes

• anything that does not change the chemical structure of the molecules (basically, anything that makes it get bigger, get smaller, or change shape)

• Freezing, melting, evaporating, condensing, crushing, stacking, increasing, dissolving…

Chemical Changes

• anything that changes what you have into something else

(difficult or impossible to reverse)

• Ex: Burning paper

(C6H12O6)n + O2 = C + H2O = CO2

Paper + Oxygen turn into Water, Carbon Dioxide, and Carbon dust.

Mixture

• two or more substances mixed together - not in fixed proportions

- not chemically bonded together

- can be separated

*Blood is a mixture.

Solution

• a homogeneous (evenly combined) mixture of two or more substances *frequently (but not necessarily) a liquid

• Ex: sugar water

• Solute – the part that

dissolves (sugar)

• Solvent – The part that

it dissolves into (water)