• 6-8: 4D/M1a. All matter is made up of atoms, which are far too small to see directly through a microscope.
• 6-8: 4D/M6a. There are groups of elements that have similar properties, including highly reactive metals, less-reactive metals, highly reactive nonmetals (such as chlorine, fluorine, and oxygen), and some almost completely nonreactive gases (such as helium and neon).
• 6-8: 4D/M11. Substances react chemically in characteristic ways with other substances to form new substances with different characteristic properties.
• 9-12: 4D/H2. The number of protons in the nucleus determines what an atom's electron configuration can be and so defines the element. An atom's electron configuration, particularly the outermost electrons, determines how the atom can interact with other atoms. Atoms form bonds to other atoms by transferring or sharing electrons.

• 9-12: 4G/H2a. Electric forces acting within and between atoms are vastly stronger than the gravitational forces acting between the atoms. At larger scales, gravitational forces accumulate to produce a large and noticeable effect, whereas electric forces tend to cancel each other out.
• 9-12: 4G/H3. Most materials have equal numbers of protons and electrons and are therefore electrically neutral. In most cases, a material acquires a negative charge by gaining electrons and acquires a positive charge by losing electrons. Even a tiny imbalance in the number of protons and electrons in an object can produce noticeable electric forces on other objects.

• 6-8: 11B/M1. Models are often used to think about processes that happen too slowly, too quickly, or on too small a scale to observe directly. They are also used for processes that are too vast, too complex, or too dangerous to study.

• 6-8: 11D/M3. Natural phenomena often involve sizes, durations, and speeds that are extremely small or extremely large. These phenomena may be difficult to appreciate because they involve magnitudes far outside human experience.

How do attractive and repulsive forces act on atomic particles and influence the sharing of electrons? This interactive Flash tutorial helps students visualize what is happening in the covalent bonding process. They will view two hydrogen atoms interact to create a covalent bond, learn about patterns in the periodic table, and explore how electrostatic potential energy affects bonding.

• Physical Sciences K-8 Molecular Structures and Bonding Unit
• Physics First Molecular Structures and Bonding Unit
• Conceptual Physics Molecular Structures and Bonding Unit
• Algebra-Based Physics Molecular Structures and Bonding Unit
• AP/Calculus-Based Physics Molecular Structures and Bonding Unit