Periodic table facts
What are 4 main types of compounds?
oxide, acid, base, salt
What element make balloons float ?
Helium
What is a compound?
A substance formed by two or more elements bonded with chemical bonds
When atom losses or gains an electron, it becomes an_
An ion
How many elements are in the Periodic Table?
more than 100, 118
Ionic bonds are formed between __ , and the electrons are ___
Give an example:
metal and non-metal, transferred
MgCl2, NaF,
What elements make up table salt?
Na and Cl
What has the ability to turn blue litmus paper red? They are composed of __ cation
Acids
H+
What is the name given to the electrons in the highest occupied energy level of an atom?
Valence electrons
On which side of the stair steps are the nonmetals?
Right side
Covalent bonds are formed between __ , and the electrons are ___
Give an example:
Non-metals Shared
H2O, CO2, NH3, C6H12O6
From what element is the hardest to take electron from the outermost energy level?
Fluorine
What compound is composed of hydroxyl group?
Write a formula of one such compound.
Bases
NaOH
Chemical compounds form the way that each atom, by gaining or sharing electrons, has eight electrons in its highest occupied energy level. We call this __ rule.
Octet rule
The two most reactive elements in the Periodic Table
Francium and Flourine
One type of intermolecular bond is __ bond.
Give 2 examples:
hydrogen
between water molecules
between 2 strands in DNA molecule
secondary, tertiary structure of protein
What is called air based on its composition?
What two elements are mostly found in the air?
homogeneous mixture
nitrogen and oxygen
Acids and bases are measured by the scale called__.
The bottom of the scale from_ to _ is occupied by __,
the top of the scale from_ to _ is occupied by __.
pH Scale
1 to 6 - acids
8 to 14 - bases
Two types of ions are _ and _.
The first one has _ charge, an example is _
The second one has _ charge, an example is _
anion and cation
negative - O-2
positive - Ca+2
Can elements be broken down? Why?
Give an example.
No, there is no example, unless we consider radioactive decay
Give/write on the board an example of a compound formed by 2 types of bonds. Explain
Na2SO4
Cu(OH)2
Classifying matter by its composition, we have _ and _
Within the first one we have_ and _, and within the second one we have _ and _
pure substances and mixtures
elements, compounds
homogeneous and heterogeneous
Write and balance the reaction between calcium hydroxide and hydrochloric acid.
Ca(OH)2 + 2HCl = CaCl2 + 2H2O
What are Delocalized Electrons?
In what type of bonding are they present?
What very important property do they provide?
Electrons not associated with a single atom, free to move through entire structure.
Metallic bond
Electrical and thermal conductivity