Compounds and Formulas Matter elements and such Stability

Compounds and Formulas Matter, elements, and such.

Stability and Compounds o o o Sodium is a soft, silvery metal. Chlorine is yellow-green gas. Why is sodium chloride (Na. Cl) a brittle crystalline solid?

Compounds o o Some of the matter around you is in elemental form. It is not combined with any thing (Oxygen you’re breathing) Most of the elements, however, are in the form of compounds.

Compounds o o Compounds have their own properties, and they are completely different than the individual elements. Iron + Oxygen makes rust. Copper + Sulfur makes verdigris. Silver + sulfur makes tarnish.

Formulas o o o The chemical symbol for sodium is Na. The symbol for Chlorine is Cl. Compounds have a chemical formula. Na. Cl is the formula for sodium chloride. H 2 O is the formula for water.

Subscripts o o o H 2 O Notice that the 2 is written in a subscript. The subscript tells how many atoms of that specific element are present in a compound. There are 2 hydrogen for every one oxygen. Fe 2 O 3?

Stability o o Some elements are more stable when ionized, than when in their natural state. How stable an element is, depends on the arrangement of electrons in the valence shell of that element.

Noble Gases o o Noble gases are the most stable elements. The reason is the configuration of their electrons: They all have complete valence shells.

Chemical Stability o o An atom is only stable when its valence shell is full of electrons. But, its hard to capture and hold electrons alone.

Other elements o o o Hydrogen has one valence electron. But its outer shell needs 2 to be complete. Hydrogen cannot capture another electron by itself, so it must find another way. Hydrogen will share an electron with another hydrogen. They will both have complete shells, and will both be stable.

Helium. o o Helium is a noble gas, and has 2 valence electrons. Helium is stable, and will rarely form compounds.

Chemical bond o o o When atoms gain, lose or share electrons with other atoms, they will stay stuck together. There is energy stored in the link between them. It is called a chemical bond.