Elements... we're all heard of them but what exactly are they? there are 118 elements: 90 naturally occurring elements and other man-made elements that exist. These elements make up everything. Literally everything, every single thing in the universe. Our video, Hunting the Elements takes a look at these elements and just a few of their millions of uses. The big question: How do elements make up everything we use?

Today in class, we looked at water on the molecular level. We discuss the meaning of chemistry and matter. We investigated a drop of water hanging from a dropper and drops of water beading up on wax paper. We also look at a molecular animation that models the motion of water molecules. We were introduced to the idea that matter is made up of extremely tiny particles that are attracted to one another. The big question: How does water behave?

Today, we looked at Chemical and Physical, Properties & Changes. A physical property is a characteristic are measurable. Characteristics like mass, length, volume.... these characteristics can be observed without changing the substance. Chemical properties are observable as well. However, they're only observable after a chemical reaction. After the chemical reaction, the substance is changed into something else. To identify if a property is chemical or physical, ask "can the property be observed without changing the identity of the substance?" If the answer is yes-- it's a physical property. If the answer is no-- it's a chemical property. 

Properties are properties... they're characteristic that something has. I'm tall, I have brown hair, I'm 6 feet and 4 inches tall. Those are some of my physical properties. My chemical properties, are a little harder too observe. I'm not flammable, I have some reactive properties but we're not going to get into that! The point is, properties are one thing, changes are another. In a physical change, the change does not change the substance's identity. No new substance formed during a physical change. My identity is Mr. K, Kinger, Nick.. that's me. if I ball up, I'm still me, my identity didn't change, just my shape. In a chemical change, the result is a new substance. Chemical changes, change the identity of the substance. If I was to jump into a tub of hydrochloric acid, I would chemically change. I would no longer be Mr. K. If you're trying to figure out if the change is chemical or physical. Ask the golden question. Is the change reversible? If the change is reversible, say, water freezing into ice. We can get the original substance (liquid water) back. A chemical change requires a chemical reaction. Like cooking an egg. once it's cooked, you can't uncook it! That's a chemical change; a new substance formed!

Hope everyone enjoyed their break! Now it's time to get back at it with our chemistry fun. Today we took a look at subatomic particles. Protons, neutrons and electrons make up atoms. Each particle has a positive, negative or neutral charge. When these net charges are balanced, there is no attractive force between objects. However, if an object has a more negative charge, the object will attract a neutral or more positive charged object. If two objects hold the same charge, they will repel. Today we used our bodies and gave up some of our electrons in the name of science! The big question: why do objects attract or repel other objects?

Homework 4/1:

1. None

Due in class:

1. None

Yesterday we learned how the charges of subatomic particles and how objects of similar charges repel where as objects of opposite charges attract. But in the world of chemistry these numbers are not random. The values of electrons and neutrons are related to the number of protons. Also known as the atomic number. The identity of an atom determined by the number of protons in the nucleus. Today, we are going to observe the patterns of subatomic particles and how each is related within the atomic structure. During our game we will use clues to identify the atoms and the values of their corresponding subatomic particles. The big question: why do objects attract or repel other objects?

Now we know how protons, neutrons and electrons are related and how we can use these numbers to identify the atom. We know that protons and neutrons are all held in the nucleus of an atom.. so where do the electrons live? Welcome to the "electron city" population -- see the atomic number. All electrons want to live close to the nucleus (town hall) the street they need to live on, the electron orbital however, has a limit. Only 2 electrons can live on the street closest to town hall. After these two spots are full, the electrons move in to the streets in an outer orbital. The number on the next street is 8. This continues until all the orbital are full. Electrons don't just freely move around. Their location is determined by these orbital. We will finish our game by using electron configurations to identify atoms. The big question: why do objects attract or repel other objects?

So atoms are made of tiny things called subatomic particles. These particles each have a charge unique to them which holds the atom together. Protons live with the neutrons in the nucleus of an atom while electrons go around the nucleus in orbital. The outer most electrons are known as valance electrons. These valance electrons are responsible for bonding as well as giving properties to the atom. These valance electrons are also responsible for the atoms bonding to other atoms. When atoms come together and bond they form molecules and compounds. Today we will look at some common molecules and explore how they bond. Atoms can bond as long as they follow the universal rules of bonding. All bonding spots have to be full - this is how molecules find new friends. The big question: How are molecules formed?

Today we will review for our test tomorrow. We've learned a lot over the last few weeks about chemistry. Lets be sure we answer any questions we may have. We also went over types of bonding. An atom can bond in one of two ways. Covalent bonding - this is when an atom shares electrons with another atom until their outer orbital is full and happy. Another type of bonding is ionic bonding - sometimes is just easier to lose an electron rather than gain seven. When this happens the atom that lost an electron becomes a cation and the atom that picked up that electron becomes an anion. They have an opposite charge which causes them to attract. The big question: How are molecules formed?

Everyone did extremely well on the test! Well done. As you know, next week starts our PSSAs. The next time we will have science will be Friday, April 15 (Tax day!). Have a good week and good luck on the PSSAs!