Biology Ch. 2

Anything that takes up space and has mass. Matter is made up by elements

Capacity to do work and cause change. TWO TYPES: Potential and Kinetic

Substance that cannot be broken down to other substances by simple chemical means

2 or more different elements in a fixed ratio

• Living Organisms need elements in small amounts (trace elements)
• Ex: Fe, Zn, l, Se, etc. <0.01%

Smallest unit of matter that still retains the property of that element

Subatomic particles in an atom that is electrically neutral. Deduced by subtracting the mass number (superscript) by the atomic number (subscript).

Subatomic particle of an atom that is positively charged and is in the nucleus. Defined by the atomic number of an element, which is unique to each element. (¹²₆C, ¹³₆C, ¹⁴₆C are all carbon because they all have 6 protons, unique to Carbon)

Subatomic particle of an atom that is negatively charged and is kept in the orbital region of the atom by the positive charges of the proton.

The number of protons in an element (unique), found as a subscript ₂He

Small unit of measurements to describe weight of subatomic particles such as protons and neutrons.

Protons and neutrons packed in a tight core and is positive by the protons.

Sum of protons and neutrons, found on the left side of the element in superscript. EX: ¹¹C

Energy that matter has because of its location or structure (like water in a dam). Has more energy at top and less at the bottom.

Atoms usually have the same number of protons and neutrons of a given element; however, isotopes have more neutrons of a given element that give it a greater mass. Ex. Carbon 12, Carbon 13, Carbon 14.

Electrons energy level is correlated with the average distance to the nucleus. First shell, closest to nucleus, electrons have the lowest energy level.

Electron shell is where electrons reside, each with its characteristic average distance and energy level.

Chemical Behavior is due to electrons in the outermost shell: valence electrons.

The outermost shell of an atom. Atoms with similar numbers of electrons in Valence Shells exhibit same behavior.

is where electrons spend 90% of their time.

is the attraction of Atoms, combine by sharing or transferring valence electrons.

Sharing of electrons (covalent/cover/warm). Ex Hydrogen with 1 valence electrons, share electrons with other hydrogens.

2 or more of the SAME atoms when joined by COVALENT bonds.

Notation that represents atoms and bond. EX. H-H (shows that it is shared)

H(sub2) shows that it has 2 Hydrogen molecules.

Bond by sharing 2 electrons (such as oxygen)

bonding capacity is the atom's valence. (2 fulfill atoms outermost valence shell)

Bond when atoms electronegativity are similar to each other. Ex. 2 Hydrogen bonds with the same electronegativity.

Stable vs. Unstable Isotopes: C12 and C13 are stable (don't have tendency to lose particles). C14 is unstable where nucleus spontaneous decays, giving off particles and energy.

Is the particular attraction of atom's electrons of a covalent bond. Stronger the electronegativity, stronger it pulls other shared electrons.

Bond when one atom is more electronegative than another, it is a polar covalent bond.

A charged atom/molecule

Positively charged ion.

Negatively charged ion.

Cations (positive charge) bond with Anions (negatively charged). Any two oppositely charged ions can form an ionic bond.

Compounds formed by ionic bonds such as NaCl (Sodium Chloride)

Nonpolar covalent bonds maybe be somewhat give a charge in some regions (electrons are not evenly disbursed); hence, bonds are weak and only happens when atoms or molecules are really close to each other. Ex. gecko lizard's hands can climb up walls.

Takes place when chemical bonds make or break to change the composition of matter.

Starting material of a chemical reaction.

The end result of a chemical reaction. Reactants form the end results (product)

reactions create a dynamic equilibrium that has no net affect and has stabilized at a particular ratio.