Matter
Give 2 examples of each
•Homogeneous mixtures (solutions): mixed uniformly; cannot see their components
•Example: air (nitrogen, oxygen, hydrogen), steel (iron and other elements)
•Heterogeneous mixture: have different components that you can see
•Example: beach sand, salad dressing
1.How many elements are there?
How many elements occur naturally on Earth?
how/where are other elements made?
118 elements
90 elements occur on earth naturally
other elements are synthesized in labs
What teacher/chemist is known as the father of the periodic table
Dmitri Mendeleev
Mendeleev’s periodic table was ordered by increasing atomic mass:
How is the modern periodic table organized?
The modern periodic table is organized by atomic number
Three broad categories of elements shown on the periodic table (color coded)
what are they?
Metals
Semi metals
Non metals
What is Matter
And
give the difference between a mixture and a pure substance
Anything that has mass and takes up space
a mixture is made up of 2 or more pure substances and can be separated by physical means
a pure substance is made up of one type of particle and cannot be separated by physical means
.What distinguishes one element from another?
they have varying properties
different names
different symbols
How did Mendeleev organize his periodic table
By increasing atomic mass
Who was the scientist that determined an elements atomic number?
what does the atomic number represent
•Henry Moseley: scientist that determined an element’s atomic number (the number of protons in an atom)
Elements in Groups 3 to 12 are called what?
Transition Elements
What happens during a chemical reaction?
List 2 examples of chemical reactions
A chemical reaction is when one or more pure substances interact to form a different substance or substances
•Elements can react to form compounds
•Compounds and elements can react to form new compounds
•Compounds can break apart to form elements and simpler compounds
examples: explosives, a candle burning, burning wood, baking a cake
all elements have chemical names and symbols
Properly write out at least 3 different chemical symbols
Au
Na
Cl
C
O
What was the genius behind Mendeleev's organization of the periodic table
•Left gaps in his periodic table to predict the existence of elements not yet found yet
why were elements arranged by atomic number and not by atomic mass?
•When elements are arranged according to increasing atomic number, the elements fit perfectly and do not require re-ordering
•Elements of Groups 1, 2, and 13 to 18 are called main-group elements or representative elements
Define what physical and chemical properties are
Provide as many examples of each that you can
Physical properties: characteristics that can be observed or measured without changing is chemical identity
appearance, texture, color, odor, melting point, boiling point, density, solubility, polarity
Chemical properties: describe the ability of matter to react with another substance to form different substances
combustibility, lack of reactivity, reactiveness to oxygen, reactiveness to acid
Chemicals names usually are based from what language ? and named after what sources?
Based on Latin words, countries, names of famous scientists
Mendeleev was able to predict the existence of elements not yet discovered and was able to predict their properties because
Mendeleev knew they would have properties similar to elements already discovered in the same Families
list all the pieces that can be found in a periodic table tile?
there are 5!
Atomic number
Atomic mass
Chemical symbol
Chemical name
Ion charge
List the properties of
Metals
Non Metals
Semi Metals
where can these be found on the periodic table?
Metals:
Shiny and hard (typically)
Malleable and ductile (can be made into sheets and drawn out into wires)
Conducts electricity and heat
Found to the left of the zigzag line on the periodic table
Semi Metals:
•Also known as metalloids
•Found in the green boxes in a staircase shape
•Have physical and chemical properties of both metals and non-metals
•Shiny (like metals)
•Brittle and not ductile (like non-metals)
Poor conductors of heat and electricity (like non-metals)
Non Metals:
•Not shiny, malleable, or ductile
•Poor conductor of electricity and heat
•Found to the right of the zigzag line on the periodic table
•Generally gases or brittle, dull solids
Elements and compounds are examples of pure substances. describe what an element is and what a compound is
Give an example of each
•Elements: made up of one type of atom; cannot be broken down into simpler substances (example: gold)
•Compounds: made up of two or more elements; can be broken down into simpler substances (example: sodium chloride)
What types of elements sometimes have 3 letters as symbols
•Synthetic or unnamed elements have placeholder names or three-letter symbols
the horizontal Rows and vertical columns on the periodic table are known as
Vertical : groups
Horizontal: periods
list all the pieces of the periodic tile for O
Atomic number: 8
Atomic mass: 16
Chemical symbol: O
Chemical name: Oxygen
Ion charge 2-
What makes Hydrogen an unusual element
Hydrogen:
•Usually on the left side of the periodic table
•Lightest element
•Colourless, odourless, tasteless
•Highly flammable
•Makes up over 90% of atoms in the universe.
•On Earth: Most hydrogen is found combined with oxygen as water
•does not contain any neutrons.