Presentation on theme: "Warm up Which atom best represents a Carbon atom?."— Presentation transcript:
Warm up Which atom best represents a Carbon atom?
Electron Cloud Electron Cloud It’s a small world after all PLEASE!!!! Do not sing this terribly annoying song
Valence electrons The electrons swirling around the nucleus of an atom are called the electron cloud. This ‘cloud’ contains all the electrons in a given atom.
Electron cloud The electron cloud has different energy levels that electrons must follow in, called electron shells. We will only look at the first three. The following shells can hold: 1 st shell-Up to 2 electrons 2 nd shell- up to 8 electrons 3 rd shell- up to 18
Valence electrons Vocab: Valence electrons: Electrons on the outermost shell of an atom. So how many valence electrons do these atoms have?
Models model- a simple version of a more complicated system or concept. Models make something easier to understand.
Draw in IAN Just label the shells The Bohr Model The Bohr model- shows ALL the electrons, protons, and neutrons in an atom.
Electron dot diagrams Scientist use a more simple way to represent atoms and their valence electrons than the Bohr model. An electron dot diagram shows ONLY the valence electrons of an atom and its name. Next, draw the same carbon atom using the electron dot diagram.
Bohr model vs. Electron dot Draw in IAN the C (Carbon atom) and draw an arrow to the valence electrons. Bohr model Electron Dot model
This is a perfect time to introduce the atoms rule of eight Vocab: Rule of eight- all atoms want to have 8 valence electrons to fill up their outer shell. The atom will do whatever it can to make the rule of 8.
This is a perfect time to introduce the atoms rule of eight The atom will give valence electrons away or steal from other atoms to make their outer shell have 8 electrons. Electrons, not money---->
An atom reacts with another atom based on its # of valence electrons. (electrons on the outer shell) An atom is unstable and wants to react because of its # of valence electrons. EVERY chemical reaction happens because # of valence electrons
Lets do this on the board!!!!! This ‘stealing’ and ‘sharing’ is how ALL reactions happen!!!
Another example. The electron is stolen by the Cl atom and the Na atom wants to get rid of it Why?