Chemistry Part II Electrons and Bonding.

Electrons surround the nucleus of an atom. Electrons are negatively charged particles. Electrons are negatively charged particles. They are responsible for chemical reactions. They are responsible for chemical reactions. The have a very, very, very, very, very, very small mass. The have a very, very, very, very, very, very small mass. 8ft2 ft

Electrons are found around the nucleus in clouds otherwise known as energy levels. The 1 st energy level around a nucleus can hold a max of 2 electrons The 1 st energy level around a nucleus can hold a max of 2 electrons The 2 nd energy level around a nucleus can hold a max of 8 electrons The 2 nd energy level around a nucleus can hold a max of 8 electrons The 3 rd Energy level can hold a max of 18 electrons. The 3 rd Energy level can hold a max of 18 electrons.

How it works nucleus Lithum has an atomic number of 3, so there are 3 protons. This means there are 3 electrons Place electrons around the nucleus by first putting them on the first energy lever. 1 st level max is two electrons. Once you hit the max go to the next level. Electron 2 nd Energy Level 1 st Energy Level

You Try Magnesium it has an atomic number of 12. Nucleus

How to do it. Nucleus 1 st level can hold a max of 2 electrons Put two electrons on the 1 st level

How to do it. Nucleus 1 st level can hold a max of 2 electrons 2 nd level can hold a max of 8 electrons Place 8 more electrons on the 2 nd level

How to do it. Nucleus 1 st level can hold a max of 2 electrons 2 nd level can hold a max of 8 electrons 3 rd level can hold a max of 18, but we need to only place =12 Place 2 more electrons on the 3 rd level

Answer to Magnesium it has an atomic number of 12. Nucleus 2+8+2=12

Your turn to determine the protons, neutrons, electrons and then draw the atoms. 9 Fluorine F Protons = Neutrons = Electrons =

Bonding When atoms join together or bond it is due to the creation of a more stable piece of matter. When atoms join together or bond it is due to the creation of a more stable piece of matter. Electrons filling up the outer energy levels to their maximum is what creates stability. Electrons filling up the outer energy levels to their maximum is what creates stability. Outer energy levels are called valance levels. Outer energy levels are called valance levels. Stable = outer electrons maxed on 2 nd level. 8 valence electrons. Unstable = 1 electron, when it can hold a max of 8. 1 Valence electron.

Bonding There are stable atoms on the periodic table, we call them the noble gasses. There are stable atoms on the periodic table, we call them the noble gasses. Helium, neon, argon, krypton, xenon, radon. Helium, neon, argon, krypton, xenon, radon. All of them have full valence levels. All of them have full valence levels. Outermost levels are at their max or full. Outermost levels are at their max or full.

Luckily not all atoms are stable so we get a variety of chemicals and two major types of bonding. 2 Major types of bonding. 2 Major types of bonding. Covalent Bonding is the sharing of electrons. Covalent Bonding is the sharing of electrons. Ionic bonding is the transfer of electrons. Ionic bonding is the transfer of electrons.

Covalent Bonding Covalent bonding is when atoms share electrons to create a full valence shell. Covalent bonding is when atoms share electrons to create a full valence shell. Hydrogen is unstable, it has 1 valence electron in the 1 st energy level. Hydrogen is unstable, it has 1 valence electron in the 1 st energy level. Oxygen is unstable because it has six electrons in the 2 nd energy level. Oxygen is unstable because it has six electrons in the 2 nd energy level. When 2 hydrogen combine with 1 oxygen all atoms have full valence electrons by sharing the electrons. When 2 hydrogen combine with 1 oxygen all atoms have full valence electrons by sharing the electrons.

Examples of Covalent Bonds Chlorine Gas Chlorine Gas Glucose Glucose Protein Protein

Ionic Bonds – Transfer of Electrons to Create Full Valance Energy Levels. When an atom looses or gains an electrons we call them an ion. When an atom looses or gains an electrons we call them an ion. If you loose an electron, then you become slightly positive. If you loose an electron, then you become slightly positive. If you gain an electron, then you become slightly negative. If you gain an electron, then you become slightly negative. Opposites attracts +/- Opposites attracts +/- You get an ionic bond You get an ionic bond

Ionic Bonds are best represented by salts. Sodium Chloride Sodium Chloride Potassium Chloride Potassium Chloride Magnesium Chloride Magnesium Chloride

Exit Pass What are valence electrons? What are valence electrons? What does stability mean when we talk about bonding? What does stability mean when we talk about bonding? What is the maximum electrons allowed on the 1 st, 2 nd, and 3 rd energy levels? What is the maximum electrons allowed on the 1 st, 2 nd, and 3 rd energy levels? What is the difference between an ionic and a covalent bond? What is the difference between an ionic and a covalent bond?

Darth Monkey Street Says, “Electrons are responsible for all chemical reactions. If you get negative with me I will react with my light saber on you!” “Electrons are responsible for all chemical reactions. If you get negative with me I will react with my light saber on you!”