Chemistry Chapter 4

modern atomic theory

concept that all elements are composed of atom

diatomic

elements thats exist as 2 atoms

atoms

building blocks of matter

elements are made of the same kind of …

atom

compound

2 or more different kinds of elements

what 3 particles are atoms composed of

electrons , protons, and neutrons

proton, p+

nuclear particle with a positive charge

neutron, n

nuclear particle with no electrical change

electrons, e-

nuclear particle with a negative charge

Neutral atoms have the same number of

protons and electrons

atomic symbol

a 1 or 2 letter notation used to represent an atom

mass number (a)

is the total of protons and neutrons in the nucleus

atomic number(z)

the total number of protons in the nucleus

what is the nuclide symbol for the atom that has 19 protons and 20 neutrons

39/19 K

Nucleus consits of 17 protons and 18 neutrons, what is the nuclide symbol

35/17 Cl

Isotopes

atoms with the same atomic number but they have a different mass number