Cht 2: Chem Flashcards
(24 cards)
Matter
Anything that has mass and takes up space
Ex. Solids. Liquids. Gas.
Element
Cannot be broken down further by a chem reaction
Ex. Na. Cl.
Compound
2+elements combined
Ex. NaCl
5 elements that make up 97% human body
Carbon Hydrogen Nitrogen Oxygen Phosphorus (CHiNOP)
Atoms
Smallest unit of matter.
Has a central nucleus surrounded by electron shells
Proton
+ Positive
In the nucleus
Atomic number
Neutron
Neutral (n)
In the nucleus
Electrons
Negative
In shells
Octet rule
Atomic number
Atomic number
Top number
Tells number of protons and electrons
Atomic mass
Bottom number.
Sum of protons and neutrons in the nucleus.
Protons - neutrons =mass
Octet rule
Te inner most shell hold up to 2 electrons. The remaining shells hold 8
Atom is stable when…
The outter shell is full
The chemical behavior (reactive?) depends on…
The valence shell (# e- on the outter shell)
Electrically neutral
Number of + protons = - electrons
Isotopes
Atoms of the same element (same number of protons) but with varying numbers of neutrons.
Relative abundance
When isotopes are average to provide the atomic mss shown on the periodic table
Radioactive isotopes
Are unstable and give off radiation as they break down.
Find the age of fossils
Ions
Atoms that have gained or lost one or more electrons. Then are no longer electrically neutral.
+ions give
-ions steal
Atoms stable when 8e
Chemical bonds
Ionic
Covalent: polar and non
Hydrogen
Ionic bonds
Attraction between oppositely charged ions
Ex. Na+Cl-
Covalent bonds
When atoms share one or more electrons in order to fill outer shells.
Single and double covalent bonds.
Ex. H2 and O2
Polar molecules
Shared electrons spend more time around the more stronger positive nucleus. (-)(+) or (+)(-)
Ex h2o
Nonpolar molecules
Shared electrons evenly
(-)(-)or (+)(+)
Ex h2
Hydrogen bonds
Weak attractions between the opposite poles of 2 different polar molecules.
Water: surface tension
