unit 1 Flashcards
chemistry of life (18 cards)
define “matter”
anything that has mass and takes up space (has volume)
states of matter:
solid, liquid, gas
define “element”
a substance that cannot be broken down by chemical means into any simpler substances; elements are composed of only one type of atom
the six main elements found in all living organisms
carbon, hydrogen, nitrogen, oxygen, phosphorus, sulfur (CHNOPS)
define “atom”
smallest unit of matter that still retains the properties of an element
atom is composed of?
protons, neutrons, electrons
in the nucleus:
protons and neutrons
in orbiting clouds (electron shells) around the nucleus:
electrons
what determines which element an atom is?
the number of protons
define “isotopes”
atoms of the same element (have the same number of protons) but have a different number of neutrons
define “radioactive decay”
when the nucleus of a radioactive isotope breaks down into a more stable atom
define “radioactive dating”
using the half-like of certain isotopes, scientists can determine the age of fossils, rocks, and other relics in this process
define “tracer”
a molecule that was synthesized (“labeled”) using a certain radioactive isotope. the radioactivity of that isotope can then be tracked by scientists to see where that molecule ended up
define “compound”
consists of two or more elements chemically bonded together
define “ionic bonds”
forms when atoms TRANSFER electrons to one another and become ions (positively or negatively charged atoms)
define “covalent bonds”
form when atoms SHARE electrons with other atoms
define “ionic compounds”
; consist of positively and negatively charged ions (charged atoms or particles), typically a metal and a nonmetal element
; can usually dissociate in water - meaning water can separate the ions from one another, breaking the ionic bonds between them. this allows the compound to dissolve in water
