# Atomic Structure.

## Presentation on theme: "Atomic Structure."— Presentation transcript:

Atomic Structure

Matter is made up of atoms.

Atoms Three basic parts Protons, Neutrons, Electrons

Protons and neutrons are located in the nucleus.
Electrons are located in the electron cloud. There are many levels (shells) within the electron cloud. 1st shell holds up to 2 electrons 2nd shell holds up to 8 3rd shell holds up to 8 (for the first 20 elements)

Electrons on the outer shell are called valence electrons and are the part of the atom involved with chemical bonding to make molecules and compounds.

Most of the mass of an atom comes from the protons and neutrons.
Electrons have very little mass. Most atoms are empty space within the electron cloud. The mass of an atom is calculated by adding the number of protons and neutrons. What is the atomic mass off this atom?

Drawing Atoms Practice Drawing an atom with 4 protons, 4 neutrons, and 4 electrons.

Drawing Atomic Models 3 protons, 4 neutrons, 3 electrons

Atomic Charge Most stable atoms are neutral overall even though they have charged particles. This is because stable atoms have the same number of protons (+ charges) and electrons (- charges). The charges will cancel each other out.

Review What are the 3 basic parts (particles) of the atom?
Which particles are located in the nucleus? Where are electrons located? How many electrons can the 1st electron shell hold? 2nd ? 3rd ? Electrons in the outer most shell are called __? Why are these electrons special?

Review 6. Where does most of an atoms mass come from? 7. Why are atoms mostly empty space? 8. How do you calculate the mass of at atom? 9. Why are stable atoms electrically neutral overall?

Constructed Response Draw an atom with 5 protons, 6 neutrons, and 5 electrons. Label the particles as well as their charges. Label the electron cloud and nucleus. Be sure to draw the correct number of electron shells and put the correct number of electrons in each shell. Calculate the mass of the atom (SHOW YOUR WORK!). Describe why your atom is considered electrically neutral overall. Be neat and precise. This will be graded.