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Delve into the realm of atoms, ions, and molecules to explore their structures, interactions, and bonds forming elements and compounds. Understand how atoms combine to create the diversity of matter around us.
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Main Idea: All living things are based on atoms and their interactions Section 2.1 Atoms, Ions, and Molecules
Atoms Atoms are: • Building blocks of all matter • NOT living • Similar in structure
Electrons Atomic structure- Atoms are made of 3 types of subatomic particles • Protons + • Neutrons • Electrons - Protons Neutrons
N N Nucleus of an Atom • Nucleus is the core of an atom. It contains: • Protons • Have a positive charge • Each type of atom has a specific number of protons (Atomic Number) N • Neutrons • Have no charge / neutral Nucleus
e- e- Electron Cloud of an Atom The electron cloud is the area that surrounds the nucleus and contains electrons • Electrons : • have a negative charge • orbit the nucleus of the atom Electron Cloud
Neutron Proton Electron Atom Structure -1 +1 +1 -1
Atoms have a balance of positive protons and negative electrons which gives them an overall neutral charge
- + IONS An atom or group of atoms that has an electrical charge because it has gained or lostelectrons
- + IONS • An atom can never lose or gain protons because that is its “identification number”.
- + IONS • BUT • An atom CAN lose or gain its electrons. • When they do, they become ions.
Remember – Electrons have a negative charge. If an atom “loses negativity ” it becomes “more positive” If an atom “gains negativity” it becomes “more negative”
Positive Ions are written with a positive sign. Ex. H+ Negative Ions are written with a negative sign. Ex. OH-
An atom that does NOT gain or lose electrons has a Neutral charge. It is NOT an ion. Its number of negatively charged electrons is equal to /balanced by the number of positively charged protons. Neutral atoms are written without a sign. Ex. Ra
Atomic Combinations Main Idea: Atoms join to form elements and compounds
Element A substance that is made of one or more of the sametype of atom. Examples include: O2 – Oxygen we breath O - Oxygen atom 03 – Ozone molecule
Element Symbols Each element is represented by its elemental symbol – a 1-3 letter abbreviation with 1st letter capitalized
Compound A substance made of two or more different elements
Hydrogen atoms - green Oxygen atoms - black Water Molecule Hydrogen Peroxide Molecule
Carbon Dioxide – CO2 • Water – H2O 2 Categories of Compounds – based on whether they contain carbon atoms Compounds that : DO contain carbon atoms - organic compounds DO NOT have carbon atoms- inorganic compounds
Isomers – molecules that have the same type and number of elements but are arranged differently
Lesson Topic: Chemical Bonding Main Ideas: *Atoms are joined by bonds to form elements and compounds *Bonds involve the atom’s electrons
*Each “energy level” only holds a certain number of electrons E level one - 2 electrons E level two - 8 electrons E level three - 8 electrons
Electrons in the outermost energy level are called valence electrons
Atoms are reactive (likely to bond) when there aren’t enough valence electrons to fill their outermost energy level. • Atoms gain, lose or share valence electrons to fill the level.
Intramolecular bond – attractive force between atoms in the same molecule.Two Types of Intramolecular Bonds:1. Ionic2. Covalent
Ionic Bonds • Attractive force between oppositely charged ions. • Ion – a charged atom due to gaining or losing electrons.
Compounds formed between Ionic bonds are called ionic compounds. Sodium chloride crystal (NaCl) – Table salt
Covalent Bonds • Atoms share electrons. • Compounds formed by covalent bonds are called molecules.
Single covalent bond – each atom shares one of its valence electrons - Methane Single bonds
Double covalent bond – each atom shares two of its valence electrons Double bonds
Bond energy -the measure of bond strength in a chemical bond. It is the amount of heat Erequired to break the molecule into its individual atoms. Covalent bonds are stronger than ionic bonds – takes more bond energyto break them apart
Ionic Bonding https://www.youtube.com/watch?v=n8D6UOefwMo