chem review

the atom contains

subatomic particles:

proton

neutron

electron

proton

positive charge

neutron

neutral charge

electron

negative chwrge

atomic number

“Z”

number of protons in the nucleus

nuclear charge = +Z

atomic mass

“A”

whole number

rounded off avg atomic mass

mass of most common isotope

sum of protons and neutrons

neutron #

A -Z

cation

pos charge

anion

neg charge

isotope

two or more atoms of an element having the same number of protons but different # of neutrons (mass is diff)

most active metal

francium

most active non metal

fluorine

BrINClHOF

Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, Fluorine

metalloids

boron, silicon, arsenic, tellurium, astatine, germanium and antimony

nucleon

protons + neutrons

what particles have the same mass?

neutron and proton

atoms in farther out shells have

more energy

atomic radius

decreases across a period

increases down a group

ionization energy

increases across a period

decreases down a group

electronegativitu

increases across a period

decreases down a group

how to find atoms in a formula

multiply coefficients by subscripts and add

all chemical reactions have a concentration of

mass charge and energy

use roman numerals when:

the element (a metal) has more than one charge in a formula and you need to specify which charge

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thomson rutherford

gold foil experiment

concluded that the atom is mostly empty space, the center of the atom is dense, small, and positive

bohr model

explains that Electrons move around a nucleus, but only in prescribed orbits, and If electrons jump to a lower-energy orbit, the difference is sent out as radiation

dalton

hard invisible sphere no particles

liquids at stp

mercury and bromine

j.j thompson

discovered negatively charged atomic particle