Unit 1 Intro & Measurement Flashcards
Describe the solid state of matter
-definite volume
-maintains shape regardless of container
-particles are close together and in a regular pattern
-high density
Describe the liquid state of matter
-definite volume
-takes shape of its container
-particles are close together and move past each other -difficult to compress
Describe the gas state of matter
-no definite shape
-assumes shape of container
-no definite volume
-particles are far apart and move around randomly
Describe the plasma state of matter
-highly charged particles
-high kinetic energy
-no fixed shape or volume
-less dense than solids or liquids
-ions roam freely
What is a mixture?
-composed of more than 1 component
-varying composition
-any combo of solid, liquid, or gas
-can be separated into its components by physical process
Examples of mixtures
-sugar dissolved in water
-salt water
-air (mix of gases)
-solutions, colloids, suspensions
What are the 2 types of mixtures & describe them
-heterogeneous mixture = visually distinguishable components (salt & pepper, oil & water)
-homogeneous mixture = appear uniform throughout, all solutions are homogenous not all homogenous mixtures are solutions (milk: uniform appearance, but still has fat particles floating around)
What is matter?
anything that has mass / takes up volume
What 2 categories can matter be divided into based on its PHYSICAL changes ?
pure substances & mixtures
What is a pure substance?
-composed of only a single component (atom or molecule)
-has a consistent composition
-cannot be broken down into other pure substances by a physical change
-either an element or a compound
How is a pure substance different from a mixture?
-mixtures are composed of more than one component
-mixtures have varying composition
-mixtures can be separated into their components by physical process
What is an element?
a pure substance that cannot be broken down by a chemical change
What is a compound?
a pure substance formed by chemically joining two or more elements chemical combo of 2 or more elements (salt = NaCl, water H2O)
What two things can be separated by CHEMICAL means?
compounds & molecules
What is an atom?
the building blocks of all matter
What is a molecule
-a group of atoms bonded together
-the smallest unit of a chemical compound that can take part in a chemical reaction
-elements contain molecules, compounds are molecules of that compound
What are diatomic molecules?
molecules that contain 2 atoms that are chemically bonded
What are the 7 naturally occurring diatomic molecules?
-Hydrogen (gas)
-Nitrogen (gas)
-Fluorine (gas)
-Oxygen (gas)
-Iodine (solid)
-Chlorine (gas)
-Bromine (liquid)
What are physical properties?
things that can be measured without changing the composition of the sample under study
Examples of physical properties
-mass
-color
-volume
-density
-solubility
-odor
-melting point / boiling point
What are chemical properties
chemical reactions / changes
Examples of chemical properties
-flammability
-toxicity
-heat of combustion
-pH value
-rate of radioactive decay
-chemical stability
What are the signs that a chemical change occurs?
-color change
-formation of precipitate
-formation of gas
-odor change
-temperature change
-production of light
-volume change
-change in taste or smell
-formation of bubbles
“mega” prefix meaning
10^6
“kilo” prefix meaning
10^3
“deci” prefix meaning
10^-1
“centi” prefix meaning
10^-2
“milli” prefix meaning
10^-3
“micro” prefix meaning
10^-6
“nano” prefix meaning
10^-9
What are the building block elements of the human body (96%)
-oxygen
-carbon
-hydrogen
-nitrogen
What are the 3 subatomic particles that atoms are composed of?
-protons
-neutrons
-electrons
Describe the nucleus
-location of protons and neutrons
-dense core of the atom
-location of most of the atom’s mass
Describe the electron cloud
-location of electrons
-comprises most of the atom’s volume
-mostly empty space
Atomic number is equal to what?
the number of protons in the nucleus
What are isotopes?
atoms of the same element that have different #s of neutrons same atomic number, different mass number
What are principal energy levels / shells (n)?
the region around the nucleus that is occupied by electrons with particular energy
Which electrons are closer to the nucleus?
electrons in the lower numbered shells
Which electrons are further from the nucleus?
electrons in higher numbered shells
What are the subshells labeled as & how many orbitals do they each have?
- s = 1 orbital
- p = 3 orbitals
- d = 5 orbitals
- f = 7 orbitals
How many electrons can each orbital hold?
2
What are orbitals?
region of space where the probability of finding an electron is high
List the properties of metals
-located on the left side & middle of the periodic table
-good conductors of heat and electricity
-malleable (thin sheets)
-ductile (thin vials)
-shiny solids at room temperature (except mercury (Hg) which is a liquid)
List the properties of nonmetals
-located on the right side of the periodic table
-have a dull appearance
-usually poor conductors of heat & electricity
-can be solids, liquids or gases at room temp
List the properties of metalloids/semi-metals
-located on the solid line that starts at boron (B) and angles down towards astatine (At)
-have properties intermediate between metals and nonmetals
-**only 7 metals are metalloids: boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), & astatine (At)
What is specific gravity?
-a quantity that compares the density of a substance with the density of water at the same temperature
What is the density of water?
1g/mL
How many elements are there?
117
Major minerals:
elements that are needed (at least 100mg daily)
-magnesium & sulfur
Mass number =
number of protons + number of neutrons
of neutrons =
atomic mass - atomic number
H
hydrogen
He
helium (noble gas)
Li
lithium (alkali metal)
Be
beryllium (alkaline earth metal)
B
boron (metalloid)
C
carbon (non-metal)
N
nitrogen (non-metal)
O
oxygen (non-metal)
F
fluorine (halogen)
Ne
neon (noble gas)
Na
sodium (alkali metal)
Mg
magnesium (alkaline earth metal)
Al
aluminium (metal)
Si
silicon (metalloid)
P
phosphorous (non-metal)
S
sulfur (non-metal)
Cl
chlorine (halogen)
Ar
argon (noble gas)
K
potassium (alkali metal)
Ca
calcium (alkaline earth metal)
Sc
scandium (transitional metal)
Ti
titanium (transitional metal)
Mn
manganese (transitional metal)
Fe
iron (transitional metal)
Co
cobalt (transitional metal)
Ni
nickel (transitional metal)
Cu
copper (transitional metal)
Ge
germanium (metalloid)
As
arsenic (metalloid)
Br
bromine (halogen)
Kr
krypton (noble gas)
Ag
silver (transitional metal)
Sb
antimony (metalloid)
Te
tellurium (metalloid)
I
iodine (halogen)
Au
gold (transitional metal)
Hg
mercury (transitional metal)
Pb
lead (metal)
What is atomic weight?
the weighted average of all the masses of the naturally occurring isotopes of a particular element (located below the chemical symbol)
What is the unit for atomic weight?
amu (atomic mass units)
how do you calculate amu?
(fraction (%) of 1 isotope x mass of isotope 1) + (fraction of isotope 2 x mass of isotope 2)…
what is natural abundance?
the amount the particular isotope/element is naturally occurring
isotopic abundance needs to be:
in decimal form
halogens
-only exist as two atoms together (diatomic)
-very reactive
noble gases
-very stable
-rarely reactive with other elements
alkali metals & alkaline earth metals
-soft* shiny metals
-good conductors of heat and electricity
what is the formula for calculating how many electrons each shell can hold ?
2n^2
What are valence electrons?
Valence shell = the outermost shell (highest value of n), the electrons in that shell are valence electrons
What is the Lewis structure?
electron-dot structure , it represents the valence electrons of a particular element
Why does atomic size increase as we go down a group on the periodic table?
Because the number of shells increases
Why does atomic size decrease as we go left to right on the periodic table?
the number of electrons is increasing, therefore attracting more energy and shrinking its size
What is ionization energy?
the energy needed to remove an electron from a neutral atom
Why does ionization energy decrease as we go down the periodic table?
valence electrons get farther away from the positively charged nucleus
