atoms everything is made of
TRANSCRIPT
Atoms are the basic units of all matter.
• Proton - A positively charged particle in the nucleus of an atom.
• Neutron - A neutral particle in the nucleus of an atom.
• Electron - negatively charged particle orbiting the nucleus.
• Nucleus - center of the atom, composed of protons and neutrons.
• Orbital - Energy levels in the cloud of electrons surrounding the nucleus.
Atoms make up all of the 118 known ELEMENTS
• Elements are pure substances that cannot be broken down into any other substance by chemical or physical means.
• Elements are identified by the number of protons in their nucleus. This is called their ATOMIC NUMBER
Atoms are often drawn like this:
Electron Proton Neutron Orbital
This is an atom of the element Beryllium.
It has 4 protons, 4 electrons, and 4 neutrons
But remember:• This is only a model. Atoms do not really
look like this. This just helps us to visualize the particles that make up an atom.
• In reality, atoms are mostly empty space. There is a big distance between the nucleus and the electrons.
• Electrons never stop moving. They whiz around the nucleus around 22oo km per second. The orbitals (energy levels) show us the “altitude” they are in.
The Periodic Table of Elements
• This is a chart that organizes everything in the universe - everything! How exciting is that?
• Each element has a square on the periodic table that gives us important information about it.
• A very smart man named Mendeleev invented it. My hero!
Info on the PT1. Name of the Element
2. 1 or 2 Letter symbol. First letter is capitalized the second is not.
3. Atomic Number - number of protons.4. Atomic Mass - an average of the number of
protons and neutrons in the nucleus. Neutrons can be different without changing the element.
Nitrogen
7
14.007
Atomic Number: the number of protonsNitrogen has 7 protons and 7 electrons
Symbol
Name
Atomic Mass: Protons + NeutronsNitrogen has 7 neutrons on average.
Rules for Drawing an Atom
1. Atomic Number = the number of protons.
2. The number of electrons = the number of protons. (not always but we will get into that later)
3. The number of neutrons = the Atomic mass - the atomic number. Just round the mass to the nearest whole number.
and then it gets complicated…
• Electrons get put in orbitals around the nucleus.• We will concentrate on elements that use only three orbitals.
#1-20 on the PT. After that it gets insane -something to look forward to in high school!
• 1st orbital holds 2 electrons• 2nd orbital holds 8 electrons• 3rd orbital holds 8 electrons• You start filling from the inside orbital and the fill outwards.
Each orbital must be full before you move to the next one.
Now you try!
5
BBoron
10.811
How many protons does Boron have?
How many neutrons does Boron have?
How many electrons does Boron have?
How many orbitals will Boron have?