Exam 1 study(Chemical elements)

Nucleus

center of atom

protons

single + charge with a mass of 1 amu

Neutrons

No charge with a mass of 1 amu

Atomic mass

total number of protons and electrons + neutrons

Electrons

single - charge, much low mass

An is electrically neutral because…

the number of electrons is equal to the number of protons

Valence electrons

Electrons in the outermost shell that determine the bonding properties of the atom

Levels on an electrons start with what but continue with what?

Starts with 2, continues with 8

To balance, what must the amount of electrons do?

Equal the amount of protons

Isotopes

Same atom but a different amount of neutrons to change the mass

Radioisotopes

Unstable isotopes that give off radiation as they decay into their stable form

How many radioisotopes does every element have

One

What happens when humans are exposed to radioactivity

It destroys our molecules and produces dangerous free radicals

Free radicals

smaller parts that release from the decaying molecule that shouldn’t exist and is dangerous to the body

Ions

charged particles with an unequal amount of electrons and protons

Ionization

transfer of electrons from one atom to another

Anion

atom that gains electrons(a net negative charge)

Cation

atom that loses electrons(net positive charge)

Ions with opposite charges are…

attracted to each other and can form ionic bonds

Ionic bonds form between what

Anions and cations

Molecules

chemical particles composed of two or more united atoms from a chemical bond

compound

molecules composed of two or more different elements

Molecular formula identifies what?

constituent elements and how many atoms are present

Chemical bonds

forces that hold/attract molecules together

Single covalent bond

One pair of valence electrons that are shared between atoms

Double covalent bonds

Two pairs of valence electrons are shared between atoms

Nonpolar covalent

Has the strongest chemical bond, electrons are shared equally

Polar covalent

electrons are shared unequally

Bonds ranked by strength from greatest to least

Covalent, Ionic, Hydrogen, Van der Waals

Hydrogen bonds

a weak attraction between a slightly positive atom in one molecule and a slightly negative atom in another molecule

Hydrogens are important to physiology because…

of protein structure, DNA structure and water molecules

Van der Waals

weak, brief attractions between neutral atoms

What do fluctuations in electron density do in electron clouds?

They create polarity and can attract adjacent molecules in the region for a very short time

Ionic

One atom completely gives away one or more electrons to another atom

Hydrogen

The partially positive H from one molecule is attracted to the partially negative O on another molecule

Element

simplest form of matter to have unique chemical properties

minerals

inorganic materials extracted from soil and passed to humans