Chapter 2 Flashcards
Atom
smallest unit of matter, nucleus contains protons/neutrons, orbitals in the electron cloud contain electrons
Molecule
2+ atoms joined by a chemical bond
Element
different types of atoms, 90 naturally occuring
Atomic Number
the number of protons an atom has
Atomic Weight
average weight of all isotopes found on earth (found on periodic table)
Isotope
atoms of the same element that have different # of neutrons, most elements have a few isotopes
Valence Shell
the outermost electron shell of an atom
Octet Rule
atoms reacting to obtain full valence shell
Electronegativity
How much an atom will attract shared electrons across a bond. O is more electronegative compared to N, C, H. N is more electronegative compared to C, H. C and H are similar in electronegativity.
Ion
A charged atom
Anion
a negative ion
Cation
a positive ion
Explain what is created if you change the number of protons
a different element
Explain what is created if you change the number of neutrons
becomes an isotope
Explain what is created if you change the number of electrons
becomes an ion
ionic bonds
electrical attraction between 2 atoms
covalent bonds
sharing electrons between 2 atoms
hydrogen bond
weak electrical attraction between MOLECULES
non-polar covalent bond
electrons are shared equally, usually same element (H2), or with similar electronegativity (C and H)
polar covalent bond
electrons are not equally shared (O is more electronegative than H, electrons spend more time around O than H)
solute
something that dissolves in a solvent
solvent
liquid in which one or more substance can dissolve
solution
solute and solvent
Acid
LOW pH, high H+ concentration, something that can donate H+
Base
HIGH pH, lowers H+ concentration, usually OH- ions, something that reacts with H+, removing H+ from the solution
Buffer
Readily absorbs excess H+ or OH-, keeping body pH neutral
Density of Ice
4 hydrogen bonds, in a lattice, more spread out than liquid, less dense= floats
High Specific Heat
the amount of energy required to raise the temp of 1 gram of water 1 degree C
High Heat of Vaporization
the amount of energy required to change 1 gram of water to gas. takes a lot of energy.
Cohesion
attraction between 2 like things (water beads)
Surface Tension
the capacity of a substance to withstand being ruptured when placed under tension or stress
Adhesion
attraction between 2 different things (water attracted to glass, spreads out)
Capillary action
adhesion allows for water to be attracted to the charged glass walls of the capillary tube
Relate the structure/ bonds of water to the properties above in one sentence.
Hydrogen bonds between polar water molecules account for all the above properties of water.
