Lesson 14 Atoms, Elements & the Mole

1. Lesson 14 Atoms, Elements & the Mole Objectives * The student will define an element. * The student will define and explain the parts of an atom. * The student will convert between names and symbols for commonly used elements. * The student will define a mole, and explain what it is used for.

2. Standard Deviants • Tape 1 IB The ELEMENTS

3. Atoms, elements, names, and symbols. a. “Atom” comes from Greek for indivisible b. The atom is recognized as the fundamental unit of matter c. Atoms contain smaller parts, known as protons, neutrons, and electrons i. Protons are subatomic particles with a charge of +1, a mass of 1 atomic mass unit (AMU), and are found in the nucleus of an atom. ii. Electrons are subatomic particles with a charge of –1, a mass which is approximately 1/1800th that of a proton (and therefore usually considered to have zero mass), and are found in the space outside the nucleus of an atom. iii. Neutrons are subatomic particles with no charge, a mass of one atomic mass unit (AMU), and are found in the nucleus of an atom.

4. iv. Drawing of atomic model:

5. d. Variations i. Each element has a unique number of protons ii. Electrons are arranged differently depending on the atom iii. Different forms of the same element can have different numbers of neutrons e. The properties of elements vary i. They vary in a pattern ii. When organized by this pattern, they form the “periodic table” of elements

6. f. The periodic table shows all the elements i. It lists elements and symbols, among other things ii. Symbols are one, two, or three letters. iii. Single symbols are capitalized – ex H, N, O, F iv. Two letter ones: First capitalized, second lowercase – ex He, Br, Li v. Three letter ones: not a permanent name – only first is caps – Uuh, Uuo vi. Some symbols come from the English name. Some come from Greek or Latin names for the elements. vii. You need to know the following ones: 1. Elements 1-88

7. II. The Mole a. This unit is designed to bring the infinitesimally small numbers associated with nuclear particles and single atoms up to something we can work with in the real world b. A mole is defined as the fundamental SI unit used to measure the amount of a substance, or a collection of 6.022137 x 1023 particles. c. It is abbreviated mol or n. d. This number was chosen because there are exactly that many particles of a substance in the atomic mass of an element when it is expressed in grams. i. Example – There are 6.022137 x 1023 particles in 12.01 g of carbon ii. There are 6.022137 x 1023 particles in 35.45 g of chlorine.

8. Molar Measurement Virtual Lab 2 video

9. e. This number, 6.022137 x 1023 , is usually rounded to 6.02 x 1023 , and is known as Avogadro’s number. f. Comparisons of a mole i. If 5 billion people were to count 1 atom per second, they would need 4 million years to count to 6.02 x 1023 atoms. ii. If the surface of the United States was covered by 1 cm3 cubes, the pile of cubes would be 50 miles deep. iii. In comparison, 18 ml of water contains one mole of water molecules.

10. Avagadro’s Number virtual Lab 2 video

11. Questions: 1. What is an element? 2. Make a chart listing the three particles that make up an atom, their locations, charges, and masses. 3. What is a mole?