Unit 11: Atomic Structure and Nuclear Chemistry

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1 amu
atomic mass of a proton
1 amu
atomic mass of a neutron
atomic mass of an electron
electrical charge of a proton
electrical charge of an electron
inside nucleus
location of a proton
inside nucleus
location of a neutron
in the surrounding electron cloud (orbiting around the outside)
location of an electron
The atomic number is determined by the number of _____ in an atom
protons electrons
In a neutral atom, the number of ______ equals the number of _______
protons neutrons
The atomic mass is equal to the mass of the ______ plus the mass of the ______
atomis mass atomic number
To find the number of neutrons in an atom you subtract the _____ by the _____
protons electrons
The charge on an ion indicates an imbalance between ______ and _______
negative charge
More electrons than protons in an atom creates a
positive charge
Less electrons than protons in an atom creates a
atomic number
The _____ is equal to the number of protons
atomic number atomic masses
Elements come in a variety of isotopes, meaning they are made up of atoms with the same ______ but different _______
the number of neutrons
these atoms differ in….
nuclear energy
-expensive: power plants to build
-used in medicine
-used in foods: longer lasting, kills pathogens that spoils it
-energy: no sun or wind needed, not burning fossil fuels
-used in smoke detectors
one of the pieces of evidence for the fact that atoms are made of smaller particles come from the work of Marie Curie (1876-1934)
Marie Curie
discovered radioactivity the spontaneous disintegration of some elements into smaller pieces
Types of radiation
Alpha (á), Beta (β), Gamma (y)
Alpha (á)
a positively charged helium isotope (we usually ignore the charge because it involves electrons, not protons and neutrons) ⁴₂He
Beta (β)
an electron ⁰-₁e
Gamma (y)
pure energy called a ray rather than a particle ⁰₀y
other nuclear particles
neutrons, positron, proton
a positive electron ⁰+₁e
usually referenced to as hydrogen -1 ¹₁H
_____ rays pose the greatest external risk
______ pose the greatest risk if emitted from ingested radioactive particles because it’s the biggest, whatever it touches it destroys
Alpha (á), Beta (β), Gamma (y)
_____ is stopped first at paper, _____ is stopped next at 0.5cm of lead, _____ is last and is stopped at 10cm of lead
Reactanta yields ____ in nuclear decay
(# of) determine the element
(# of) determine the isotope
(# of) determine the charge
atoms of the same element that have different # of neutrons
an atom with a charge
positive ion
negative ion
atom with no charge
coal, natural gases, fossil fuels
nuclear reactions
_____ involve changes in the number of protons and/or neutrons in the nucleus of an atom
The changes in the number of protons and/or neutrons in the nucleus of an atom during nuclear reactions are called…because an atom of one element is changed into an atom of a different element. During which, the nuclear particles may be absorbed and/or emitted along with a release of energy
natural radioactive decay
transmutations occur by natural radioactivity
natural radioactivity
the ability of a nucleus to emit a nuclear particle and energy without external stimulation
certain nuclei having a large mass are bombarded with special particles that cause the nuclei to split into two nuclei each having a smaller mass
nuclei of light elements are combined to form heavier nuclei
Alpha particle symbol
Proton symbol
the most common hydrogen nucleus is a ____
electron symbol
neutron symbol
positron symbol
Beta particle
an electron is also called a
Gamma ray symbol
nuclear reactions
reactions in which the nuclei of unstable isotopes, called radioisotopes, gain stability by undergoing changes, and these changes are accompanied by emission of large amounts of energy
nuclear reactions
_____ are not effected by changes in temperature, pressure, or the presence of catalysts
radioactive decay
does not require energy
alpha radiation
consists of helium nuclei that have been emitted from a radioactive source
alpha particles
are emitted during alpha radiation and contain 2 protons/ 2 neutrons and have a double positive charge
nuclear equations are always…
paper of a thin piece of lead
alpha particles can be stopped by
Beta radiation
consists of fast moving electrons formed by the decomposition of a neutron in an atom
Beta particles have ____ charge/ mass than Alpha particles
wood or aluminum foil
beta particles can be stopped by
Gamma rays
have no mass or charge
thick pieces of lead or concrete
Gamma rays are stopped by
above the atomic number ___ stable nuclei have more neutrons than protons
is a particle with mass of an electron but has a positive charge
all nuclei with an atomic numb greater than __ are radioactive, they have too many neutrons/ protons
half life
the time required for one-half of the nuclei of a radioisotope sample to decay to products
after one half life, ____ of the original radioactive atoms have decayed into atoms of a new element
nuclear fusion
small nuclei combine, ²₁H + ³₁H -> ⁴₂He + ¹₀n + Energy, occurs in the sun and other stars
half life
the amount of time it takes for half a sample to decompose
Absorbes, Bombard, Capture
particle on the left of the equation (key words)
Decay, Emission
particle on the right of the equation (key words)
radioactive decay
is an attempt to “correct” the ratio of neutrons to protons
when the neutron to proton ratio is _____ then it looses or captures particles
Transuranium elements
elements beyond 92 (after uranium, transuranium) made starting with a Gamma reaction
nuclear fission
-breaking down of an unstable nucleus
-starts stable and to make it unstable they hit a nucleus with a neutron to regain stability, it splits into 2 different elements
Categories: Nuclear Chemistry