Skin Elements Sunscreen. Introducing: Skin Elements Organic Sunscreen.
ELEMENTS
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Transcript of ELEMENTS
ELEMENTS
Remember:• Atoms of one type form an element
– A bunch of gold atoms form gold…etc.• Elements are the simplest form of a
substance • Every element is unique and has its own
chemical and physical properties
Compounds and Molecules
• A molecule is formed when two or more atoms join together chemically.
• A compound is a molecule that contains at least two different elements.
• All compounds are molecules but not all molecules are compounds.
• The number of outer or “valence” electrons in an atom effects the way an atom joins with other atoms.
• The way atoms join determine many properties of the element.
• This is why elements within a group usually have similar properties.
Each group has distinct properties
• The periodic Table is divided into several groups based on the properties of different atoms.
• Atoms whose shells are not full tend to interact with other atoms and gain, lose, or share electrons
HYDROGEN (H)Atomic number = 1
CARBON (C)Atomic number = 6
NITROGEN (N)Atomic number = 7
OXYGEN (O)Atomic number = 8
Electron
Outermost electron shell (can hold 8 electrons)
First electron shell (can hold 2 electrons)
• When atoms gain or lose electrons• Charged atoms called ions are created
– Lose electrons---positive charge– Gain electrons--- negative charge– Like charges repel and opposite charges attract
Ionic bonds
NaSodium atom
ClChlorine atom
Na+
Sodium ionCl–
Chloride ion
Sodium chloride (NaCl)
Na Cl Na Cl
+ –
Ionic Bonds• Electrons are transferred• Forms between metals and
nonmetals• Dissolve easily in water, usually