Semester 1 Final Flashcards
Matter has
substance, stuff, it is anything that has mass and volume
___is the property of matter that can be measured
mass
the amount of space matter takes up is called
volume
Mass is measured in
milligrams(mg), grams(g)(1000mg), and kilograms(kg)(1000mg)
Volume is measured in
milliliters(mL), and liters(L)(1000mL)
calculating the conversion of some units to another unit is
information given x conversion factor(s) = information sought
elements
building material of all matter, the purest form
compound
different elements combined in specific ratios, represented by a chemical formula
ratios of the elements in compounds __ change
never
ratio of carbon to oxygen atoms in CO2
1:2
molecules
multiple atoms of the same element combined, not compounds
Aqueous Phase
when a substance forms a mixture with water ex. seawater, vinegar. It is not a liquid
Homogenous Mixture
one phase, solution or pure substance ex. sugar + water
Heterogenous mixture
2 or more phases, can be separated by filtration or extraction ex. sand + water
Reactivity
property describing how easily an element will combine with other substance to form new compounds
the more reactive an element is,
the more rapidly it combines with other elements
Atomic Mass
mass of an atom, measured in atomic mass units(amu)
Periodic table
arranges the 118 chemical elements into rows and columns, based on a set of repeating properties
Vertical columns
called groups
horizontal rows
called periods
in chemistry, positive ions can be called
salts
the elements on the periodic table can be grouped into
metals, metalloids, and nonmetals
atom
the smallest particle of an element retaining its identity in a chemical reaction; made of subatomic particles
subatomic particles
protons, neutrons, and electrons
proton
subatomic particle with a positive charge equal to about 1 amu, p+
electron
subatomic particle with a negative charge equal to about 0.000055 amu, e-
neutron
subatomic particle with no charge equal to about 1 amu, n0
nucleus
dense central core of atoms made up of neutrons and protons - makes up most of an atom’s mass
electron cloud
electrons surrounding, orbiting, the nucleus - makes up most of an atom’s volume
atomic mass unit(amu)
unit used to measure the mass of subatomic particles
atomic number
number of protons in an atom, which determines the identity of an element
normal atoms have what charge and why
neutral because the number of protons and electrons is the same
Mass number
total number of protons and neutrons in an atom
Isotope
atom with the same number of protons but a different number of neutrons, therefore, different atomic numbers
to calculate average atomic mass of isotopes of an element
create weighted average, so use ratios as percentages that multiply amus and add together
(0.9)(20amu)+(0.09)(22amu)+(0.01)(21amu)= 20.19amu
transmutation
conversion of one element into an atom of another element, occurs naturally thru radioactive decay, when nuclei emit particles an rays
Nuclear Stability is controlled by two forces
electrostatic repulsion force and the strong nuclear force
electrostatic repulsion force
repels positively charged particles, so when protons in an atom increase, the force increases
strong nuclear force
short range force on atoms independent of charge, when overall number of subatomic particles in nucleus increases, force increases
the large an atom’s nucleus, the more the __ force overpowers the __ force
repulsion, strong
an imbalance in force in an nucleus creates
instability
Valley of stability
atoms with atomic numbers under 80
alpha decay
decay of an element to stabilize nucleus that involves the emission of an alpha particle, or the nucleus of a helium, 2 neutrons and 2 protons
alpha particle(4/2 He) emitted and atom changes
222/88 Ra –> 4/2 He + 218/80 Rn
quirks
make up neutrons and protons,
-up quirks
-down quirks
proton have 2 up quirks and 1 down quirk
neutron has 1 up quirk and 2 down quirks
beta decay B- (negative)
decay of an element to stabilize nucleus that involves the transformation of a neutron into a proton, creating a high energy electron
90/39Y – B- –> 90/40 Zr
In beta decay, the atomic number __ while the mass number __
changes, remains the same
beta decay B+ (positive)
decay of an element to stabilize nucleus that involves the transformation of a proton into a neutron, creating a positron(positive electron)
49/25 Mn –> 49/24 Cr + 0/+1 e
light is made up of
waves with varying wavelength
the shorter the wavelength of a light
the more energy it has
blue light has __ wavelengths while red light has __ wavelengths
longer, shorter
when heated, some electrons get “excited”, moving
father from the nucleus to the next orbit, but its instability causes it to fall to a lower energy state by emitting a photon of specific energy
an energy input causes electrons to move up to
excitation, followed by an energy output, leading to relaxation
electron shells
circles, orbits, or electrons around the nucleus
each electron shell represents a discrete
(specific) energy level
Atomic Emission Spectrum(AES)
pattern formed when light emitted by an element, unique to every element, because an atom in a gas state emits light when energy is absorbed