Periodic Table
As of 2016 how many known elements were in existence?
118
What is a pure substance made from only one type of atom?
An element
Most elements are found on their own in nature. True or False?
False. Only a few elements are found naturally on their own. Most are found as compounds - bonded to something else.
80% of the periodic table are classified as...
metals
All matter is classified as either ___________ or ________________
Mixture or a pure substance
How many elements are naturally occurring?
92, however 2 were at one point were synthesized and then found in nature.
We cannot see these basic building blocks with our naked eye - we must use a powerful microscope
an Atom
All elements on Earth were made from...
Stars - through nuclear fusion, a reaction in which two or more atomic nuclei are combined to form one or more different atomic nuclei.
non-metals
Mixtures can be ______________ or _________________
Homogeneous (the mixture is uniform - the same throughout) or heterogeneous (mixture is different throughout)
The periodic table is organized by what characteristic of an element?
It's atomic number - which is the number of protons found in the atom of an element
A single substance that is made from two or more elements that are chemically combined
a Compound
A few elements are naturally radioactive. What does this mean?
BONUS: give an example
It means that the core of their atom, the nucleus, spontaneously falls apart into smaller fragments in a process called nuclear decay or radioactive decay.
Uranium is an example
These elements are brittle and will break apart easily when someone attempts to mold them or bend them.
Nonmetals
Pure substances have unique physical and chemical properties. List 5 properties you could use to determine the identity of a pure substance
Luster, density, boiling/melting/freezing point, malleability, reaction with acids/water, crystalline structure, etc.
How many columns and how many rows are on a periodic table?
18 columns. 7 rows.
Sodium + Chlorine = NaCl (Salt)
this is an example of a
Compound
How are artificial elements created?
By bombarding heavy, stable elements with smaller particles or other elements
Highly conductive elements would be found closer to what side of the periodic table?
right
Crystal growth is a character trait of a pure substance. What two factors influence crystal growth?
the amount of dissolved substance forming the crystal
and the temperature of the solution
Give the names of two element families and their column number and 1 key character trait
Nobel Gases: column 18 - all inert gases/colourless/gases in natural state
Alkali Metals: column 1 - all shiny metals, highly conductive, react instantly with water
Compounds, like elements, are made up of atoms. In compounds, atoms are joined together to form _________.
Molecules.
Which is a particle that is made up of one or more elements that are chemically combined
Only two elements came from the Big Bang, what were they?
Hydrogen and Helium
What is the name of the elements that are found around the descending staircase? What are their character traits?
Metalloids
semi-conductive, appear to be metal but are brittle, have character traits of metals and nonmetals, usually are solid, often form alloys with other metals
nucleation site