Atomic Structure

Gold is an element. An element is a substance which cannot be broken down into simpler substances under normal circumstances. This means that if you break gold down into smaller and smaller pieces, it will still be gold. Gold is made of nothing . . . but gold.

Salt is not an element. Salt can be broken down into simpler substances--sodium and chlorine.

Gold cannot be broken down into any other substances. The smallest, tiniest piece of gold is an atom of gold. An atom is the smallest unit of an element.

The smallest particle or piece of gold is an atom of gold. Carbon is also an element. The smallest particle of carbon is an atom of carbon.

All atoms have 2 common structures: nucleus energy level(s)

- - Each structure is made of subparticles. + energy level protons nucleus electrons neutrons -

Carbon has 6 protons. The atomic number of carbon is 6. The number of protons in the nucleus of an atom is that atom’s atomic number. + - Carbon has 6 protons. The atomic number of carbon is 6. Gold has 79 protons. The atomic number of gold is ___. The number of protons plus the number of neutrons in the nucleus of an atom is its atomic mass.

16 Atomic mass (protons + neutrons) - 8 Atomic number (protons) ___ To find the number of neutrons in an atom, subtract the atomic number from the atomic mass. 16 Atomic mass (protons + neutrons) - 8 Atomic number (protons) ___ 8 Number of neutrons

Protons = 8 Atomic Number = 8 Neutrons = 8 Atomic Mass = 16 Energy Levels = 2 oxygen atom Electrons = 8

So far, there are over 100 known elements. A summary of each element’s atomic structure is found in the Periodic Table of Elements. more about that later . . .

N 7 atomic number state of matter element symbol nitrogen element name An example of an entry in the periodic table. atomic number 7 G state of matter N element symbol nitrogen element name 14.007 atomic mass 7 How many electrons? 7 How many protons? 7 How many neutrons?

N 7 The atomic mass is always rounded to the nearest whole number nitrogen 14.007 G The atomic mass is always rounded to the nearest whole number 14.007 to 14 26.560 to 27