GQ1 - Matter
What causes matter to change states?
A change in temperature
What makes elements reactive?
An incomplete valence level. All atoms want to have 8 electrons in their outermost electron level.
The density of a substance (its mass per unit volume) can be represented by this formula.
Density = Mass/Volume
Who discovered the hidden pattern in the elements and organized them into the periodic table?
Dmitri Mendeleev
Columns on the periodic table contain these groups of elements.
Families (e.g. Alkali Metals, Alkali Earth Metals, Halogens, Noble Gases)
Acid on limestone producing carbon dioxide gas is an example of what type of change?
Chemical change
Why do atoms bond?
Atoms bond until their valence level is complete with 8 electrons. Atoms with few valence electrons lose them during bonding. Atoms with 6, 7, or 8 valence electrons gain electrons during bonding.
As the temperature of a gas decreases, its volume decreases. (For example, if you blow up a balloon, it will shrink if you freeze it.) State the law which corresponds to this statement.
Charles' Law
These elements fall on the "stair step" of the periodic table.
Metalloids
How many valence electrons do the Halogens have?
7 valence electrons
True or false: air is a form of matter, while wind is a form of energy.
True.
How do you find an element's atomic weight/mass?
By adding the number of protons and neutrons.
A bond which consists of the transfer of valence electron(s) between atoms.
Ionic Bond
As we move from left to right on the periodic table, the number of valence electrons ______.
Increases.
This family of elements are found in the second column on the periodic table. What are they called and what do they have in common?
Alkaline Earth Metals
They are the 2nd most reactive elements.
When mixed in solutions, they are likely to have an alkaline pH (>7).
In which state of matter will atoms move faster: solid or gas?
Gas
What does the atomic number represent and why do we use it?
The atomic number represents the number of protons in an atom. We use it to arrange elements in the periodic table because no two elements have the same number of protons.
When the pressure of a gas increases, its volume decreases. (If you compress air inside a tube by pushing it down with a pump or syringe, the air inside will have more pressure.) State the law that corresponds to this statement.
Boyle's Law
Elements are categorized into ____, or horizontal rows. Elements in these rows do NOT have similar properties.
periods
Describe the Noble Gases family.
They have a full electron valence.
They are the least reactive elements.
They are gases at room temperature.
They appear in the farthest right column on the periodic table.
Consider the definition of compound and mixture, and give example(s) of each.
Compound: A substance that is made up of more than one type of atom bonded together.
Mixture: A combination of two or more elements or compounds which have not reacted to bond together; each part in the mixture retains its own properties.
Compounds: Salt (NaCl), Water (H20), Methane (CH4), etc.
Mixtures: Lemonade, salt water, a jar of jelly beans, mud, etc.
Why do some elements have decimals included in their atomic mass/weight?
Not all elements have the same number of neutrons; some can have more or less neutrons, and these are called isotopes. Since the number of neutrons can vary for some elements, an atomic mass number with a decimal is the total of the number of protons plus the average number of neutrons.
A chemical bond that involves the sharing of electron pairs between atoms.
Covalent Bond
Name the properties of metals and state where they are found on the periodic table.
Shiny, conductors, malleable; to the left of the periodic table.
This family of elements are found in the first column of the periodic table and contain very reactive elements which are malleable, shiny, and lightweight. What is the name of this family and which elements are included?
The Alkali Metals - lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr).