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MATTER. Atoms. Smallest particles of matter that has all the characteristics of an element The nucleus is the central part of an atom and contains: Protons positive electrical charges Neutrons neutral electrical charges. Atoms. - PowerPoint PPT Presentation
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MATTER
Atoms• Smallest particles of matter that has all
the characteristics of an element• The nucleus is the central part of an
atom and contains:• Protons
• positive electrical charges • Neutrons
• neutral electrical charges
Atoms• Energy levels (aka shells) surround the
nucleus and contain:• Electrons
• negatively charged particles
• The atomic number is the number of protons in the nucleus of an atom
Simple Model of Atoms
Model of an Atom
Elements & the Periodic Table
Element is a substance that can’t be broken down into any simpler substanceMost common
elements in Earth’s crust:
Matter• Elements are the basic building blocks
of minerals• Over 92 naturally known elements• Pattern of Periodic Table: elements are
organized by their properties:Rows are called periods on the tableColumns are called groups on the table
Akali Metals
Alkali Metals in Water
Periodic Table
Atomic Number
Symbol
Element Name
Atomic Mass (aka Mass Number)
Isotopes• Isotopes of an element have the same
number of protons but varying numbers of neutrons
• The mass number is the number of neutrons and protons in the nucleus of an atom
• These have different mass numbers: the sum of the neutrons plus protons
Why Atoms Bond• When an atom’s outermost energy level
does not contain the maximum number of electrons, the atom is likely to form a chemical bond with one or more atoms
• A compound consists of two or more elements that are chemically combined in specific proportions.
• An ion is an atom that gains or loses electrons
Types of Chemical Bonds
1. Ionic bonds form between positive and negative ions.
2. Covalent bonds form when atoms share electrons.
3. Metallic bonds form between two metallic ions
Bonds
Bonds
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