Why Atoms Bond
Why do atoms form chemical bonds?
To achieve STABILITY - to fill their outermost electron shell (full octet) - to maintain balanced charge
An atom that carries a net positive or negative charge by losing/gaining electrons is called an _______.
ion
Valence electrons between atoms in covalent bonds are _______.
shared
Electron Dot Diagrams show only the amount of ______ electrons.
valence
The elements that make up a compound and the exact number of atoms of each element in a unit of the compound can be shown in a ____.
chemical formula
Which group of elements is most stable and WHY?
Group 18, the noble gases. Already have full octet, 8 electrons (outer energy level shells)
In an ionic bond electrons are ___________.
Transferred creating cations (positively charged ions) and anions (negatively charged ions)
Prefixes are used in the names of atoms when they are bonded with this type of bond
Draw a dot diagram for Strontium
Sr with 2 dots
Explain two differences between an ionic bond and a covalent bond
Ionic between metals (cations) and nonmetals (anions) - covalent between nonmetals, Ionic transfer electrons - covalent share electrons, Ionic no prefixes in names - covalent prefixes in names,
How many electrons are needed in the outer energy levels of most atoms for the atom to be chemically stable?
8 (2 for H and He)
Write the chemical formula for potassium iodide.
KI
A group of covalently bonded atoms that acts together as one charged atom is a ____.
polyatomic ion
Draw a dot diagram for Chlorine
Cl with 7 dots
How many hydrogen atoms are present in one molecule of ammonium acetate, NH4C2H3O2?
7
The ____ number tells you how many electrons an atom must gain, lose, or share to become stable.
Write the name for this chemical formula MgO
Magnesium oxide
Write the chemical formula for this covalent bond: sulfur hexafluoride
SF6
Draw a dot diagram for Argon
Ar with 8 dots
Subscripts are used in chemical formulas to show the number of _______.
atoms present in the compound
In the compound Mg(NO3)2, list the name of the elements involved and the number of atoms of each.
Magnesium - 1
Nitrogen - 2
Oxygen - 6
What is the charge of phosphate in K3(PO4)
-3 (K = +1 x 3 atoms K = +3 : PO4 must be -3 for balanced charges)
Write the name for this covalent compound, P2O5
Diphosphorus pentoxide
Using dot diagrams, show how Calcium and Fluorine would bond to form Calcium Fluoride.
1 atom Ca with 2 dots and 2 atoms of F with 7 dots each. The two electrons from Ca transfer to each one of the F diagrams so that all atoms are full octets.
If nitrogen and oxygen are to form a compound, what type of bond would hold it together and why would it be that type of bond?
Covalent (2 nonmetals/anions)