Valence Electrons-The electrons that are in the highest energy level if an atom and that are involved in chemical reactions. (held most loosely)(1-8) Electron Dot Diagram- A representation of the valence electrons in an atom, using dots. Chemical Bond- The force that holds atoms together. (new substances are formed) Atomic Number - increase - number of electrons increases Ion- An atom or group of atoms that has become electrically charged. Polyatomic ion- An ion that is made of more than one atom (group of atoms that react as a unit) Ionic Bond- The attraction between oppositely charged ions. (like Na + Cl sodium chloride)(MgCl2) Ionic Compound- A compound that consists of positive and negative ions. Chemical Formula- A combination of symbols that represents the elements in a compound and their proportions. (positive first, usually a metal) Subscript- A number in a chemical formula that tells the number of atoms in a molecule or the ratio of elements in a compound.. Crystal- An orderly, three-dimensional patterns of ions on or atoms in a solid. (patterns stay the same, salt) Covalent Bond- A chemical bond formed when two atoms share electrons. (non-metals) Molecule- A neutral particle made of two or more atoms joined by covalent bonds. Double bond- A chemical bond formed when atoms share two pairs of electrons. Triple Bond- A chemical bond formed when atoms share three pairs of electrons. Molecular compound- A compound that is composed of molecules. Polar bond- A covalent bond in which electrons are shared unequally. (water) Nonpolar bond- A covalent bond in which electrons are shared equally. (carbon dioxide) Alloy- A mixture of two or more elements, one of which is a metal - stronger, less likely to react with water - think of gold - jewelry, mixed with other metals; iron - rusts when exposed to air - use steel instead (forks and spoons) (metal conducts electricity well, bends) Metallic Bond- An attraction between a positive metal ion and the electrons surrounding it. (crystal)
Key Concepts: 1 - Atoms, Bonding and the Periodic Table
The number of valence electrons in an atom of an element determines many properties of that element, including the ways in which the atom can bond with other atoms.
The periodic table gives you information about the arrangement of electrons in atoms.
The elements within a group have similar properties because they all have the same number of valence electrons in their atoms. (noble gases don't react well with others)(alkaline metals very reactive)(loose electrons easily - react well)
2 - Ionic Bonds
When an atom loses an electron, it becomes a positive ion. When an atom gains an electron, it becomes a negative ion.
Ionic bonds form as a result of the attraction between positive and negative ions.
When ionic compounds form, the charges on ions balance out.
Ionic compounds are hard, brittle crystals that have high melting points and conduct electricity when dissolved in water. (baking soda, iron rust, table salt)(salt - heat; crystal melts)
3 - Covalent Bonds
The force that holds atoms together in a covalent bond is the attraction of each atom's nucleus for the shared pair of electrons.
Molecular compounds have low melting and boiling points and do not conduct electricity. (don't conduct electricity - plastic and rubber)
In polar covalent bonds, the bonded atoms have slight electrical charges.
water attracts water ; oil attracts oil; stay away from each other - add detergent helps mix - think of washing greasy pots and pans)
4 - Bonding in Metals
Alloys are generally stronger and less likely to react with air or water than are the pure metals from which they are made.
A metal or metal alloy consists of positively charged metal ions in a "sea" of valence electrons.
The "sea of electrons" model of solid metals explains the ease with which they can charge shape, their ability to conduct electric currents, their luster, and their ability to conduct heat.
Chapter 5 - Atoms & Bonding
Valence Electrons-The electrons that are in the highest energy level if an atom and that are involved in chemical reactions. (held most loosely)(1-8)
Electron Dot Diagram- A representation of the valence electrons in an atom, using dots.
Chemical Bond- The force that holds atoms together. (new substances are formed)
Atomic Number - increase - number of electrons increases
Ion- An atom or group of atoms that has become electrically charged.
Polyatomic ion- An ion that is made of more than one atom (group of atoms that react as a unit)
Ionic Bond- The attraction between oppositely charged ions. (like Na + Cl sodium chloride)(MgCl2)
Ionic Compound- A compound that consists of positive and negative ions.
Chemical Formula- A combination of symbols that represents the elements in a compound and their proportions. (positive first, usually a metal)
Subscript- A number in a chemical formula that tells the number of atoms in a molecule or the ratio of elements in a compound..
Crystal- An orderly, three-dimensional patterns of ions on or atoms in a solid. (patterns stay the same, salt)
Covalent Bond- A chemical bond formed when two atoms share electrons. (non-metals)
Molecule- A neutral particle made of two or more atoms joined by covalent bonds.
Double bond- A chemical bond formed when atoms share two pairs of electrons.
Triple Bond- A chemical bond formed when atoms share three pairs of electrons.
Molecular compound- A compound that is composed of molecules.
Polar bond- A covalent bond in which electrons are shared unequally. (water)
Nonpolar bond- A covalent bond in which electrons are shared equally. (carbon dioxide)
Alloy- A mixture of two or more elements, one of which is a metal - stronger, less likely to react with water - think of gold - jewelry, mixed with other metals; iron - rusts when exposed to air - use steel instead (forks and spoons) (metal conducts electricity well, bends)
Metallic Bond- An attraction between a positive metal ion and the electrons surrounding it. (crystal)
Key Concepts:
1 - Atoms, Bonding and the Periodic Table
- The number of valence electrons in an atom of an element determines many properties of that element, including the ways in which the atom can bond with other atoms.
- The periodic table gives you information about the arrangement of electrons in atoms.
- The elements within a group have similar properties because they all have the same number of valence electrons in their atoms. (noble gases don't react well with others)(alkaline metals very reactive)(loose electrons easily - react well)
2 - Ionic Bonds- When an atom loses an electron, it becomes a positive ion. When an atom gains an electron, it becomes a negative ion.
- Ionic bonds form as a result of the attraction between positive and negative ions.
- When ionic compounds form, the charges on ions balance out.
- Ionic compounds are hard, brittle crystals that have high melting points and conduct electricity when dissolved in water. (baking soda, iron rust, table salt)(salt - heat; crystal melts)
3 - Covalent Bonds- The force that holds atoms together in a covalent bond is the attraction of each atom's nucleus for the shared pair of electrons.
- Molecular compounds have low melting and boiling points and do not conduct electricity. (don't conduct electricity - plastic and rubber)
- In polar covalent bonds, the bonded atoms have slight electrical charges.
- water attracts water ; oil attracts oil; stay away from each other - add detergent helps mix - think of washing greasy pots and pans)
4 - Bonding in Metals