Periodic Table Unit 3 Vocabulary Atomic Number Atomic

Periodic Table Unit 3

Vocabulary Atomic Number Atomic Mass Atomic Symbol Valence electron Orbital Electron Shell Energy Level Valence shell

Atomic Number -reflects the # of protons in the nucleus and electrons in the electron cloud of a balanced atom of that element. ATOMIC NUMBER = # OF PROTONS & ELECTRONS

Atomic Number

Atomic Mass -the sum of the protons and the average number of neutrons

Atomic Mass

# of Neutrons Atomic Mass (rounded to nearest whole number) minus # of protons AM - + p = N

AM-P=N Example

Atomic Symbol

Putting it all together Atomic Number Element Symbol Atomic Mass

Electron Orbitals aka Electron Shells aka Energy Levels -the location and the path around the nucleus where an electron can be found -the amount of energy carried by an electron in an atom

Energy Level Maximum # of Electron’s each level can hold 8 e- Nucleus 2 e-

Nucleus

Valence Shell -the outermost shell of an atom in its uncombined state -all atoms want their valence shells filled.

Valence Electron • electrons located in the valence shell • # of valence e- will determine the reactivity of the atom. • The more Valence e’s the more stable and HAPPY (Noble Gases) • The less valence e’s the more reactive and EXPLOSIVE or UNHAPPY (Alkali Earth Metals)

Dmitri Mendeleev • a Russian chemist and inventor • formulated the Periodic Law • created a version of the periodic table of elements • predict the properties of elements yet to be discovered

Periods • A row of elements in the periodic table whose elements change gradually and predictably. – 7 periods – Period # = # of shells • Period 1 = 1 shell • Period 2 = 2 shells • Period 3 = 3 shells • Etc, etc

Periods

Groups (Families) • Columns in the Periodic Table that contain elements that have similar physical or chemical properties. – 18 groups – Elements have same # of valence e • Ex. Group 13 has 3 valence e-

Groups

Metals • An element that has luster, is malleable, ductile, and is a good conductor of heat and electricity • Most are solids – Some are liquids (Mercury and Neptunium) • 91 metals

Nonmetals -Gases or brittle solids -Poor conductors -Only 17 nonmetals -include elements vital to life (P, C, O, I, N, S) Sulfur Chlorine Carbon

Metalloids -an element that shares some properties with metals and some with nonmetals. -6 metalloids Silicon

Color Your Period Table I. Label the periods. (1 -7) II. Label the groups. (1 -18) III. Color metals blue. IV. Color non-metals yellow. V. Color metalloids green. VI. Create a key to show what each color represents.