Periodic Table (notes, ws)

A Russian chemist who created an early version of the periodic table. He arranged elements by atomic mass and repeating chemical properties and left gaps for elements that had not yet been discovered, predicting their properties.

Mendeleev

A physicist who discovered that elements should be arranged by atomic number (number of protons) rather than atomic mass

Mosley

What are the 5 main characteristics of metals?

1. Shiny

2. Conduct electricity/heat

3. High melting point

4. Malleable/bendable (ductile-can be made into wires)

5. Mostly solids

What are the 3 main characteristics of non-metals?

1. Los melting/boiling points

2. Not good conductors

3. Brittle (if solid)

What do metalloids have?

Characteristics of both metals and non-metals

Electrons outermost energy level that determine the behavior of an atom are:

Valence electrons

What is so special about Neon (Ne)?

8 valence electrons = perfect electron configuration

What do elements in the same group have in common?

They have the same number of valence electrons and therefore have similar chemical properties

Which two groups are the most reactive?

7a: halogen and 1a: alkali metals

Which group is totally unreactive?

8a: noble gases

Which group is the next least reactive?

4a: carbon group

Why are noble gases stable and non-reactive?

Their outermost electron shells are completely filled

What do all elements “want”?

To reach their lowest possible energy state and become stable

Why do elements in the same group have the same behavior?

They have the same number of valence electrons in their outermost