Chap 2 -1 Flashcards
What are elements?
Pure substances
Each consists of 1 atom type
94 occur naturally on Earth
What do columns denote in periodic charts?
similar properties/ behaviors
Most of an atom’s volume is?
empty space
90% of the body is composed of?
C,H,O,N
Trace elements in the body is how much percent?
less than .01
What are atoms?
smallest particles that retain properties of an element
Describe protons
+
1amu
in nucleus
define the element</p>
Describe neutrons
O
1 amu
in nucleus
define the isotope
Describe electrons
- no weight in cloud/orbiting define behavior decide whether atoms will interact/bond
How are atoms electrically neutral?
when protons = electrons
What is the atomic number?
number of protons atom has
never changes
determines the element
What is the mass number?
number of protons and neutrons can change (neutrons)
What are isotopes?
atoms w/ variable numbers of neutrons
unstable
nucleus unbalanced
What are radioactive isotopes?
they emit energy in form of particles - radioactive decay
What are electron shells?
represent distance of electrons from nucleus
What does vacancies in the outermost shell indicate?
that its reactive
1 electron shell can hold a max of?
2 electrons
Electrons move in?
pairs in orbitals
What happens when electrons interact?
Chemical bond
Mixture/solution
What is a chemical bond?\
attractive forces that fill electron vacancies and unite atoms into molecules/compounds
