Chapter 2.5
What is the simplest element on the periodic table?
Hydrogen.
The mass of an element changes by:
Changing its number of neutrons.
What is combined to determine the mass of an atom?
Its protons and neutrons.
What are the properties of solid metals explained by?
The structure and bonding of atoms.
Why are the metals in group one more reactive than the metals in group two?
Ex: They only have one valence electron that is easily lost, while group two metals have two outer electrons that take more energy to remove.
At room temp, what is the state of most nonmetal elements?
Gas.
The charge of an element changes when:
Electrons are either gained or lost.
The modern periodic table is organized by increasing:
Atomic number.
What is the difference between polar and nonpolar molecules?
In a non polar bond, electrons are shared equally, and in a polar bond, electrons are shared unequally.
In order to have a stable arrangement of 8 valence electrons, are metal atoms more likely to gain/lose electrons.
Lose.
What is atomic number based on?
The number of protons in an atom's nucleus.
What properties do metalloids have?
The properties of metals and nonmetals. (They are semi conductors).
An element's identity can be determined from its:
Atomic number.
What do valence electrons determine?
How an element will bond.
Ionic compounds have ____ melting points, while covalent compounds have ____ melting points.
High; Low.
Mendeleev organized his periodic table in order of increasing:
Atomic mass.
Why is the atomic mass of an element not a whole number?
Because it is the weighted average of the isotopes in the element.
What is the term for atoms with the same number of protons but different numbers of neutrons?
Isotopes.
Why does a charged balloon pull a stream of water towards it?
Because water is a polar molecule, so its electrons are shared unequally. Water has a positive and negative side, so it will always be oppositely charged with a balloon.
Ionic bonds form between two ions that have what types of charges?
Opposite charges.
Where are the most reactive metals located on the periodic table?
In Group One, the first column on the left.
If you have an oxygen-13 atom but want to model an oxygen-16 atom, what do you do?
Add 3 neutrons.
What does an atom gain/lose to become an ion?
An electron.
What determines the chemical properties of an element?
The number of valence electrons that it has.
Which is the correct name for MgCl2?
Magnesium Chloride.