Review: Concept 1: Stability and Bonding

Most elements are not found by themselves in nature. Usually they are found combined with other elements.

• True

• False

What is a compound?

• A single element found in nature

• Two or more elements chemically combined

• A mixture of elements and compounds

• An element in its pure form

Na and Cl properties are very different from the properties of _______.

• NaCl

• H2O

• CO2

• O2

Tags

NGSS.MS-PS1-5

What is a chemical formula?

• A way to tell what elements and how many of each element are in a unit of a compound

• A list of all known elements

• A type of chemical reaction

• A laboratory tool

Tags

NGSS.MS-PS1-1

The chemical formula H2O represents water. How many atoms of hydrogen are in one molecule of H2O?

(a)  

Tags

NGSS.MS-PS1-1

How many atoms of nitrogen are in one molecule of NH3?

• 1

• 2

• 3

• 0

Tags

NGSS.MS-PS1-1

What is the Octet Rule?

• Atoms will gain, lose, or share electrons in order to have 8 electrons in their outer energy shell

• Atoms will always have 2 electrons in their outer shell

• Atoms do not share electrons

• Atoms only lose electrons

Stability means having a full or complete outer energy level of valence electrons.

• True

• False

Which two elements are exceptions to the Octet Rule and do not require 8 electrons in their outer energy shell?

• Hydrogen and Helium

• Oxygen and Nitrogen

• Carbon and Neon

• Fluorine and Chlorine

How many valence electrons does sodium (Na) have?

• 1

• 2

• 3

• 8