Unit 2 Test Flashcards
what are 3 subatomic particles and what does each one do
protons: determine identity of an element
neutrons: hold nucleus together and influence mass
electrons: determine the chemical properties of an element
how do their masses compare (according to 1)
protons/neutrons= same mass (1.67 x 10^-24) electrons= (9.11 x 10^-28)
how do electrons emit light?
when an electron moves from a high to a low energy level it results in a burst of light
how many electrons can be held in the third principal energy level
18
how many sublevels are in the 2nd principal level
2
how are the elements arranged on the modern periodic table
increasing atomic number
how many neutrons doe Rn-226 have?
140
How does an isotope differentiate from a neutral atom?
Isotopes have the same # of protons but a different # of neutrons.
(also all have different mass numbers)
Where are neutral atoms found?
periodic table
Difference between atomic mass and mass number? what do each represent?
atomic mass: weighted average mass of atoms in a naturally occurring sample of the element, reflects both the mass and relative abundance.
mass number: # of protons + neutrons
what is the stability of an isotope based on?
ratio of neutrons to protons
which type of nuclear emission is the most similar to high x-rays?
gamma
how does the atomic emission spectrum compare to the visible spectrum
visible spectrum: only small chunk (rainbow colors)
atomic emission: everything
what determines a element’s chemical properties?
electrons
how do elements configuration relate to their position on the periodic table
they show the amount of electrons (atomic number) and where they are located
whats the difference between an ion and a neutral atom
Ion has a different number of protons/electrons
describe modern atomic theory
electrons exist in a cloud
difference between physical and chemical change
chemical: change that produces matter with a different composition than the original matter
physical: some properties of a material change but the composition of the material does not change
signs of a chemical change
- forms a precipitate
- release of energy
- bubbles
- change of color
what types of substances cant be broken down by chemical processes
elements
differences and definitions of the different types of decay
alpha: -nucleus ejects 2 protons and neutrons simultaneously -atomic # down 2 -atomic weight down 4 beta: -neutron splits into proton and electron -atomic # up 1 -atomic weight = no change gamma: -no change, just emits radiation (deadly)
what is a half-life?
the time required for one-half of the nuclei of a radioisotope sample to decay to products
how much of a 1000g sample would be left after 4 half-lives?
500>250>125>(62.5)
what do the symbols represent in the equation:
c=(upside down)Yv
C= speed of light (m/s)
(upside down) Y= wavelength (m/s)
v= frequency (sec^-1)
what do the symbols represent in the equation:
E=hv
E= energy (joules) h= Planck's Constant (J*sec) v= frequency (hertz or sec^-1)
what is atomic number
of electrons/protons
what do the symbols represent in the equation:
a/zC
a= protons + neutrons (mass number) z= protons c= element name
what are two ways to write isotopes?
element name- mass number
mass #/protons x element name
what are the two types of isotopes
stable: nucleus stays intact
unstable: nucleus decays and emits radiation
define fission and fusion
fission: when atom divides into smaller parts
(EX: nuclear energy, bomb)
fusion: when 2+ atoms fuse together to become one
(EX: stars, new elements)
strengths of the 3 types of decay?
alpha: encounter everyday
beta: skin protects us from it
gamma: goes through everything
define atomic orbitals
space around the nucleus where the electrons exists
each principal energy level surround the nucleus has a _________
specific # of sublvls within it
each sublvl has a specific _______
shape & is designated by a letter
each sublvl can only hold a certain ________
of electrons
define aufbau principle
electrons fill the lowest energy lvls first
define pauli explusion principle
only 2 electrons can share an orbital and they have opposite spin
define hunds rule
electrons spread out of their last orbital
define light
a stream of photons (packets of energy)
what do different colors indicate
different wavelengths
what is white a combination of
all the colors (light reflects color)
different wave lengths carry different ________
amounts of energy
first step:
receive energy and become excited
when electrons get excited:
they absorb energy and move up an orbital from their ground state
when they return to their ground state:
the energy is released in the forms of light. The color of the light depends on how much color it has
define amplitude, wavelength and frequency
amplitude: waves height from bottom to top
wavelength: distance between crests (tops) of wave
frequency: # of wave cycles to pass a given point
define quantum
amount of energy to move lvls
define electron configurations
way electrons are arranged in various orbitals around nuclei
wavelength and frequency are:
inversely proportional
what is red on the visible spectrum
longest wavelength, lowest frequency
