Atomic Structures Part 1

atom

smallest particle of an element that can exist either alone or in combination; considered a source of vast potential energy

nucleus

~ very dense, very stable

~ contains almost all of the weight of the atom, because it contains the protons and neutrons

nucleons

protons and neutrons together

nuclear binding force

force holding protons together in the nucleus

electron

~ particle with negative charge

~ surrounds the nucleus and are bound to it by the electromagnetic force of attraction between particles with opposite charge

~ are positioned in shells or energy levels that surround the nucleus

proton

~ charge is equal and opposite to the charge of the electron (+ 1.6 × 10^-19

~ have a relative mass of ~ 1800 times more than an electron

~ gives the nucleus its positive charge

~ determines type of atom (element)

neutron

~ charge is neutral, meaning NO electrical charge

~ has a relative mass of ~ 1800 times more than an electron

~ outside the nucleus, they are unstable

1800

The proton and neutron have a mass approximately ______ time more than the electron

1

amu for the proton and neutron is equal to approximately ___

931 MeV

1 amu is equivalent to

atomic mass unit

what does amu stand for?

A

~ mass number

~ number of protons and neutrons in the nucleus

Z

~ atomic number

~ the number of protons in the nucleus, indicating the element

N

~ neutron number

~ number of neutrons in the nucleus

A= Z+N

what is the formula to find the neutron number?

equal

Number of neutrons in an element should be about ____ the number of protons, making the element stable.

greater

the _____ the number of neutrons compared to protons, the higher the probability the element will be radioactive