Introduction to Pre-IB Chemistry I

Transcription

1 Introduction to Pre-IB Chemistry I Unit 1, Part 1 Slides Ms. Kiely Coral Gables Senior High Pre-IB Chemistry

2 Welcome to Pre-IB Chemistry -Syllabus -Periodic Table

3 Welcome to IB Chemistry SL Some general rules and expectations: -Tardies: I will assign an Unexcused Tardy each time you are late to class without a pass. -Bathroom Pass: Next to the sink -Phones and other electronic devices: keep them out of sight during lectures, labs, assignments, etc. -Hall Passes: no exiting the first 15 minutes of class -Water: Yes Snacks: Yes Meals: No -Websites: Join the Pre-IB Chemistry class by clicking on the Add to my class list button. Not seeing an assignment because you didn t check the website is inexcusable.

4 SCIENCE FEE Science Fee: $20.00 It is due on October 1st through the Online Payment System, which is accessed through the Parent Portal

5 CALCULATOR As is stated in the syllabus, a calculator is imperative in this class. Please let me know in private if you are unable to get your own calculator.

6 Unit 1 WHAT IS CHEMISTRY? Chemistry is the study of matter, but what exactly is matter? Matter is anything and everything that you can touch, smell, see, hear, and/or taste. So chemistry is the study of everything in the physical universe.

7 What is Chemistry? Chemistry is a discipline that seeks to understand what our universe is made up of. We call the material that makes up our universe matter. Chemists therefore seek to understand: 1) the composition of matter 2) the changes that matter undergoes.

8 All physical things in our universe are referred to as matter. Matter is composed of atoms, which are made up of: protons, neutrons, electrons.

9 Structure of the Atom The word atom comes from the Greek word atomos. Coined by a Greek philosopher named Democritus in 400 B.C., the word atomos means indivisible. Democritus believed all matter was composed of microscopic, solid, indivisible particles. According to Democritus model, the atom would be a fundamental particle: the smallest particle of matter. Does Democritus model of the atom agree with our current understanding of the atom?

10 Structure of the Atom Protons and neutrons are located in the nucleus, or center, of the atom. Protons and neutrons are roughly the same size in mass. Together, protons and neutrons are referred to as nucleons. Electrons are much smaller than protons and neutrons, and are located at a very far distance from the nucleus in an area referred to as the electron cloud. Protons, neutrons, and electrons are all referred to as subatomic particles.

11 The discovery of subatomic particles, the particles that make up the atom, proved that the atom is not a fundamental particle. In fact, protons and neutrons are not fundamental either; they are made up of smaller particles called quarks. The electron is considered to be a fundamental particle since we have yet to prove that the electron is made up of smaller particles.

12 Subatomic particles are SO SMALL that instead of describing them by their actual values we describe their masses by relative values. That is why these values have no units; they are simply relative values determined by how large they are when compared to each other. Protons and neutrons are relatively the same size, they have a relative mass of 1. Electrons are extremely small when compared to protons and neutrons! They are about 2,000 times smaller than protons and neutrons, and therefore are given a relative mass of Protons are positive with a relative charge of +1; electrons are negative with a relative charge of -1; neutrons are neutral and therefore have no charge.

13 The Nucleus is VERY important! The neutron is also very important. Neutrons help protons get along. As we all know, charges that are alike repel each other. Imagine if we only had a bunch of protons trying to bunch up inside of a nucleus. It wouldn t be possible! They would all repel each other away!

14 Elements An element is a pure substance made up of a set amount of protons. For instance, if an atom has 1 proton, then it is Hydrogen (H). If an atom has 2 protons, then it is Helium (He). If an atom has 17 protons, then it is Chlorine (Cl). Each element has a unique chemical name and symbol. The chemical symbol consists of one, two, or three letters; the first letter is always capitalized with the remaining letters being lowercase. The periodic table organizes elements into a grid of horizontal rows called periods and vertical columns called groups.

15 Video Kurzgesagt - How Small is an Atom:

16 All atoms are made up from the same basic ingredients, the subatomic particles. The only difference is the recipe; the amount of subatomic particles that are present in an atom is what makes one atom distinct from another. The atomic number is the number used to organize each type of atom, (the elements), in the periodic table. The atomic number is defined as the number of protons in the atom. ONLY THE NUMBER OF PROTONS IN THE NUCLEUS OF AN ATOM ARE NEEDED TO KNOW WHICH ELEMENT THE ATOM IS. The amount of neutrons and electrons do not matter when determining the identity of an atom.

17 The periodic table is organized in order of atomic number. According to the IUPAC, (International Union of Pure and Applied Chemistry), there are 118 elements currently known to us in our universe. Therefore there are 118 distinct types of atoms that can be found in our universe or synthesized. Only 92 of these elements are naturally occurring on Earth.

18 The atomic number is the I.D. of an atom- the amount of protons in the nucleus determine what type of atom it is. Atomic number: based on the number of protons found in the nucleus. The atomic number helps identify which element an atom belongs to. Chemical symbol: each element is denoted by either one upper-case letter, or one upper-case letter followed by a lower-case letter. Relative Atomic Mass (RAM): the average mass of an atom of that particular element.

19 The atomic number, the number of protons in the nucleus of an atom, is the identity of an atom. Identify the following elements:

20 1 3 2 HYDROGEN (H) LITHIUM (Li) HELIUM (He)

21 In general, the periodic table trends from metal to non-metal when going left to right.

22 States of Matter States of matter are characterized by the different energies of the particles that the matter is composed of. The kinetic energy of the particles determines what state the matter is in. Kinetic energy is directly proportional to temperature.

23 The movement of particles are directly correlated with temperature. In brief, increases in temperature cause increases in the velocity of particles, while decreases in temperature cause decreases in the velocity of particles. Changes in volume and pressure can also directly affect the state of matter a substance is in. A phase change is a transition of matter from one state to another. Sublimation: direct conversion from solid to gas, skips liquid state; i.e. dry ice Deposition: direct conversion from gas to solid, skips liquid state; i.e. water vapor becoming frost or snow Both of these occur at characteristic atmospheric pressures and levels of thermal energy.