HONORS BIOLOGY:

As an honors biology student you are responsible for knowing the regular biology content as well as the additional information included below. 

You have different Matter and Energy Notes than the biology students in order to cover the additional information you need to know.

Periodic Table

Element Boxes: Each element is represented by a box containing several pieces of information:

• Element Symbol: A one- or two-letter abbreviation for the element (e.g., H for Hydrogen, O for Oxygen).
• Element Name: The full name of the element (e.g., Hydrogen, Oxygen).
• Atomic Number: The number of protons in the nucleus of an atom of the element. This is usually found above the element symbol.
• Atomic Mass: The average mass of an element’s atoms.

Valence electrons are the electrons found in the outermost shell (or energy level) of an atom. They play a crucial role in determining how an atom bonds with other atoms and its chemical reactivity. Here’s a deeper look into valence electrons:

Importance in Bonding:

• Valence electrons are involved in forming chemical bonds. In covalent bonds, atoms share valence electrons. In ionic bonds, one atom donates its valence electrons to another.
• Atoms tend to gain, lose, or share valence electrons to achieve a stable electron configuration, often resembling that of the nearest noble gas. This concept is known as the octet rule (for most elements), where atoms strive to have eight electrons in their outer shell. Because the first electron shell holds two electrons, the first row of elements strive to have 2 rather than 8 electrons in their outer shell.

Determining Number of Valence Electrons: Periodic Table Groups: The number of valence electrons can often be determined by the group number of an element in the periodic table. 

• Group 1 (Alkali Metals): Have 1 valence electron.
• Group 2 (Alkaline Earth Metals): Have 2 valence electrons.
• Groups 13-18: The number of valence electrons is given by subtracting 10 from the group number. For instance, Group 14 elements have 4 valence electrons, Group 15 have 5, and so on.

Lewis dot diagrams, also known as Lewis structures or Lewis dot structures, are a visual representation of the valence electrons in an atom or molecule. They are useful for understanding the bonding between atoms and the arrangement of electrons. Here’s a detailed look at Lewis dot diagrams:

Purpose and Basics:

• Valence Electrons: Lewis dot diagrams show only the valence electrons, which are the electrons in the outermost shell of an atom.
• Bonding and Lone Pairs: They help illustrate how atoms bond together (through shared pairs of electrons) and identify lone pairs of electrons that are not involved in bonding.

Drawing Lewis Dot Diagrams for Atoms:

1. Determine the Number of Valence Electrons: Use the element’s group number in the periodic table to find the number of valence electrons. For instance, carbon (Group 14) has 4 valence electrons.
2. Draw the Element Symbol: Write the chemical symbol of the element.
3. Add the Valence Electrons: Represent the valence electrons as dots around the element symbol. Place one dot on each side of the symbol (top, bottom, left, right) before pairing them up.

Drawing Lewis Dot Diagrams for Molecules:

1. Determine the Total Number of Valence Electrons: Add up the valence electrons for all atoms in the molecule. 
2. Arrange the Atoms: Identify the central atom (in biology this atom will most likely be carbon).
3. Draw Single Bonds: Connect the central atom to surrounding atoms with single bonds. Each bond consists of a pair of shared electrons.
4. Distribute Remaining Electrons:Place the remaining valence electrons as lone pairs around the outer atoms first to complete their octets (or duets for hydrogen).
5. Form Multiple Bonds if Needed: If the central atom doesn’t have an octet, form double or triple bonds by sharing additional pairs of electrons between atoms.
6. Check for Octet Rule: Ensure that all atoms (except hydrogen, which follows the duet rule) have a complete octet (8 electrons) or a duet (2 electrons for hydrogen).