Atoms, Molecules, and Compounds PDF

# Atoms, Molecules, and Compounds ## Atoms - A single element ## Molecules - 2 or more atoms of the same type bonded together ## Compounds - 2 or more atoms of different types bonded together ## Why do Atoms Bond Together? - Atoms bond to become stable - meaning they have full sets of electrons...

# Atoms, Molecules, and Compounds ## Atoms - A single element ## Molecules - 2 or more atoms of the same type bonded together ## Compounds - 2 or more atoms of different types bonded together ## Why do Atoms Bond Together? - Atoms bond to become stable - meaning they have full sets of electrons. ## Types of Bonding: 1. **Ionic Bonding**: electrons are lost by one atom and gained by another 2. **Covalent Bonding**: electrons are shared ## How do Atoms Make Ionic Bonds? - Ionic bonding occurs between metals and nonmetals. - The outermost electrons are called valence electrons - All elements need to have a complete outer shell of electrons - In ionic bonding, metals will lose valence e- to become stable and positively charged - Nonmetals will gain valence e- to become stable and negatively charged - Opposite charges attract - We often refer to atoms as having an *octet* (meaning 8) when their orbitals are full and stable ## How do Atoms Make Ionic Bonds? - How many e- does oxygen need to gain to fill its orbital? - Oxygen will gain 2e- - Because e- are negative and it gained 2 more, oxygen now has a 2- charge, written as O^2- ## How many e- does aluminum need to lose to end up with a full orbital? - Aluminum will lose 3e-. This is easier than trying to gain 5e- to fill its outermost shell. - Aluminum will have a 3+ charge since it lost 3e-. It is written as Al³⁺ ## Valence Electrons - The number of valence e- determines how elements bond - A fast way to find the # of valence e- is to use the column # of the element on the Periodic Table. - Note: On the right side - ignore the 1 in front of each column number, for example, column 17 has 7 valence e-. ## Let's try it! - How many valence e- does nitrogen have? Answer: 5 - How many valence e- does calcium have? Answer: 2 ## Lewis Dot Diagrams - A diagram that includes the element symbol on the outside. - It helps to see the important e- to predict how elements will bond. - Let's try it! ## Draw a Lewis Dot diagram for fluorine. - Find fluorine on the PT - Determine its number of valence e- based on the column number - Write the symbol - Place e- around the 4 sides before partnering ## Find a Lewis Dot diagram for fluorine and copy and paste it here for your note. ## Naming Ionic Compounds # Parts of the Atom ## The Modern Atomic Theory - Smallest unit of matter - An element is made up of the same atoms. Ex. gold is made up of only gold atoms ## Parts of the Atom - Atoms are made up of: - Electrons (e^-): negative charge - Protons (p⁺): Positive charge - Neutrons (n⁰): no charge (neutral) - Nucleus contains the protons and neutrons. The orbitals are the space around the atom and contain the electrons. ## The Structure of the Atom: Carbon Atom - Number of Particles: - # of protons = # of electrons = Atomic Number - # of neutrons = Atomic mass - Atomic Number - Note: Round the atomic mass to the nearest whole number before subtracting - i.e. Atomic mass of Magnesium (Mg) = 24.31 = 24 - i.e. Atomic mass of Aluminum (Al) = 26.98 = 27 ## Practice time! - Fluorine: p+ = 9, e = 9, n⁰ = 10 - Chromium: p+ = 24, e = 24, n⁰ = 28 # Ions & B-R Diagrams - For each element, fill in the table to determine the charge and then draw the ion B-R diagram. - Element | B-R Diagram | Lewis Dot | Ion B-R Diagram | Ion | Change - - | - | - | - | - | - - Lithium | p⁺=3<br>n⁰=4 | * | Li⁺ | Li⁺ | 1+ - Sodium | p⁺=11<br>n⁰=12 | * | Na⁺ | Na⁺ | 1+ - Beryllium | p⁺=4<br>n⁰=5 | * | Be²⁺ | Be²⁺ | 2+ - Magnesium | p⁺=12<br>n⁰=12 | * | Mg²⁺ | Mg²⁺ | 2+ - Boron | p⁺=5<br>n⁰=6 | * | B³⁺ | B³⁺ | 3+ # Periodic Table Elements Quiz 1. **What is the periodic table and what does it contain?** - The Periodic Table contains elements, these are the building blocks of all other substances. - **Element** is a pure substance that cannot be broken down into a simpler substance 2. **How is the periodic table organized?** - Columns or groups, these run vertically. Elements with similar properties group together. Some of these groups have special names. - Periods, also called rows, these run horizontally. - The Periodic Table is divided into 3 main categories: metals, metalloids, and non-metals. 3. **Alkali Metals:** are shiny, silvery, soft and highly reactive. 4. **Alkaline Earth Metals:** are shiny, silvery but not as soft or reactive as alkali metals.. 5. **Transition Metals:** are shiny, silvery and vary in hardness and strength. Often used for jewelry and building materials. 6. **Metalloids:** are properties of both metals and non-metals. It is solid at room temperature, and can conduct electricity. 7. **Lanthanides and Actinides:** are radioactive, and can have weak magnetic properties. 8. **Halogens:** are all non-metals, and are very reactive. They come in different states depending on the elements. 9. **Noble Gases:** are all non-metals, they are unreactive and stable. When excited by energy they make different colored light-neon signs, # Atom, Molecule, and Compounds. - **Atom:** a single element - **Molecule:** 2 or more atoms of the same type bonded together. - **Compounds:** 2 or more atoms of different types bonded together. - **Ionic Bonding:** electrons are lost from one atom and gained by another. - **Covalent Bonding:** electrons are shared - **Ionic bonding** happens between metals and non-metals. Metals will lose valence e- to become stable and positively charged. Non-metals will gain valence e- to become negatively charged and stable. - **Atomic # :** Tells you the # of protons and electrons. Subtract it from the mass #, and you get the number of neutrons. - **Atomic Symbol:** The one- or two-letter symbol for an element, as seen on the Periodic Table. - **Mass #:** The sum of the number of protons and neutrons in the nucleus of an atom.