CHEM 1150 Prelim #1

intensive properties

properties that don’t depend on the amount of matter present (i.e, temperature, melting/boiling point)

extensive properties

properties that are dependent on the amount of matter present (i.e., length, volume)

group 1

alkali metals

group 2

alkaline earth metals

group 3-12

transition metals

group 17

halogens

group 18

nobel gases

diatomic elements

H₂ , O₂, N₂ , F₂ , Cl₂ , Br₂ , I₂

empirical formula

the simplest formula for a compound, showing atoms of a molecule in the right proportion, but not the right amount

molecular formula

the actual formula of a compound, with the component atoms in the correct numbers

how to find the # of empirical formulas

structural isomers

molecules with the same molecular formula but have atoms bonded in different orders

spatial isomers

molecules with the same molecular formula and atoms connected to other atoms by the same types of bonds but arranged differently

cisisomer

functional groups are on the same side of the molecule

transisomer

functional groups are on opposite sides of the molecule

enantiomers

when two isomers are mirror images of each other

alpha (α) particle 

^4₂He²⁺  is emitted from the nucleus

A= decreases by 4, Z=decreases by 2

beta (β⁻) particle

⁰_-1e an electron emitted from a nucleus when a neutron converts into a proton and a positron

A = unchanged, Z = increase by 1

positron (β⁺)

positively charged “electron” emitted from a nucleus when a proton → neutron & β⁺

A = unchanged, Z = decrease by 1

electron capture

 ⁰_-1e one of the isotope’s own electrons crashes into the nucleus, converting a proton to a neutron

A = unchanged, Z= decrease by 1

nuclear transmutation

bombarding a nucleus with high energy particles (alpha particles, protons, neutrons, other atoms)

nuclear fission

the process of breaking a large nucleus into smaller pieces

critical mass ( of fissionable material)

the amount of the isotope needed to self sustain a chain reaction once it’s initiated

• if there isn’t enough material, you have a subcritical mass

supercritical mass

an amount of fissionable material that speeds up the rate of fission

nuclear moderator

a substance that will slow down the speed of neutrons so they can be absorbed by the fuel & induce fission

radioactive tracers

compounds that have a stable element in a molecule with its radioactive version

• movement is tracked by the radiation emitted