Periodic Table Trends Chapter 4 Flashcards
What is a periodic trend?
Properties that show patterns when examined across the periods or vertically down groups.
What happens when an atom forms an ion?
Rhe stability of an octet of e- enables you to predict the number of electrons to gain or loss. You can then predict the change on the ion formed.
What is the trend of the atomic radius?
Further down on periodic table = larger atomic radius
What is the trend of ionization energy?
Top left has highest ionization energy, bottom right has the lowest ionization energy
What us the trend of electronegativity
As you go down, electronegativity decreases. As you go left to right, electronegativity increases (remember that the effect from left to right is much greater than the effect going down) (hydrogen needs to go between boron and carbon)
What is electronegativty related to?
Electronegativity is related to ionization energy
What are the characteristics of metals?
Shiny, Solids, stretched and shaped, conductors of heat and electricity
What are the characteristics of nonmetals?
Solids, liquids, or gases
- Most are not solid at room temperature
- If they are a solid, they are dull and brittle
- Poor conductors of heat and electricity
What are semiconductors/ metalloids?
Contain properties of both metals and nonmetals
-Ex-Conduct electricity well but are also a liquid
What is the element that does not follow the trend of being a metalloid?
Aluminum; Because it is a metal instead
The majority of the periodic tables on the left are _______?
Metals
How do you tell if something is a metal?
One the lefthand side of the zigzag line (except for hydrogen)
How do you tell if something is a nonmetal?
If its on the right hand side of the zigzag (includes hydrogen)
How do you tell if something is a metalloid on the periodic table?
Touching zigzag line (other than aluminum)
What are the different kinds of metals?
Alkali metals, Alkali-earth metals, and transition metals
What are alkali metals?
Soft, shiny, and very reactive (column on the leftmost periodic table)
What are alkaline-earth metals?
Less reactive (Found in seconf column of the periodic table)
What are transition metals?
Have different uses,and are found in center of periodic table (from Sc to Zn columns)
What are noble gases?
Mostly non-reactive gases, very stable (elements on rightmost column of periodic table)
What are halogens?
Very active, gain one electron to form a stable compound (found on 2nd to last column of periodic table)
What are diatomic gases
Chemical elements that form stable homonuclear diatomic molecules (these 7 are H2 N2 F2 O2 I2 Cl2 Br2
What is ionization energy?
How tightly a valence is held to the electron cloud.
How does the periodic table help you figure out how many valence electrons there are?
Elements in the same group of the periodic
table (column) have the same number of valence
electrons. There is a pattern that can be
observed.
Define Shielding Effect:
Inner electrons shield the valence
electrons from the attractive force of the nucleus.
The nucleus has less pull with more shielding.
Shielding is related to the _________________ from teh Bohr Model
Number of rings
The further down you go on the periodic table, the ________ the shielding
Greater
What is the effective nuclear charge trend?
As you add more protons, to an atom in the
same energy level (ring), you increase the pull
of the nucleus on electrons.
REMEMBER: Shielding is increased with # of rings as you go down, and then increases as you go left.
-Effective nuclear charge is greater when you go down or right, because it is increasing protons.
REMEMBER: Shielding is increased with # of rings as you go down, and then increases as you go left.
-Effective nuclear charge is greater when you go down or right, because it is increasing protons.
Atoms of elements in the same
group have the __________
electrons and therefore behave
similarly
same # of valence
•All elements in a period have
their valence electrons in the
same __________
Energy Level
Electron Dot Diagrams show the ____________ of an
element.
valence electrons
What is the atomic radius?
•The atomic radius of an element is
one half of the distance between the
nuclei of two atoms of the same
element when the atoms are joined. (measured in picometers)
What is the trend of atomic radius?
Atomic radius increase as you move down because each atom has another energy level (more shielding), so the atoms get bigger.
What are the periodic trends?
As you go across a period, the radius gets
smaller.
• Electrons are in same energy level (same
shielding).
Another word for the atomic radius is ____________
Size of the atom
REMEMBER: Atomic radius gets smaller left to right, but bigger as you go down
REMEMBER: Atomic radius gets smaller left to right, but bigger as you go down
When is an ion formed?
An ion is formed when the
number of electrons changes
compared to the neutral atom.
How do atoms become ions?
Atoms become ions based on the octet rule or
duet rule to become like their closest noble gas (rightmost column)
What is the rule for changing an atom into an ion?
Just ask yourself is it easier to lose or gain a given number of
electrons to be like its nearest noble gas (group 8A).
What is the oxidation state/charge of Li? (REMEMBER oxidation state is related to changing atoms into ions)
1+; Because it has to lost 1 electron to become equal to become equal to 8A, so its 1+
What are cations?
Cations are positively charged ions • Cations form by losing electrons. • Cations are smaller than the atom they come from. • Metals form cations.
If the oxidation number is a positive charge, then it is an ____
Cation
What are anions?
Anions are negatively charged ions • Anions form by gaining electrons. • Anions are bigger than the atom they come from. •Nonmetals form anions.
If the oxidation number is a negative charge, then it is an ____
anion
What does isoelectric mean?
Isoelectric means it has the same number of electrons.
How do you order elements for isoelectric sequence?
Put K+, P3-, Cl-, Ar, S2-, and Ca2+ in order of decreasing size.
- 1st find the number of electrons each atom/ion has
- Notice they all have 10 electrons now.
- 2nd Find the number of protons for each atom/ion.
- K+ has 19 p+, P3- has 15 P+, Cl- has 17 p+, Ar has 18 protons, S2- has 16p+, Ca2+ has 20 p+
- 3rd Put them in order of increasing number of protons.
- This will be the size from largest to smallest.
- P+,S2-,Cl-,Ar,K+,Ca2+
What does ionizatio eneergy state?
Electrons are held in atoms by their attraction to the positively
charged nucleus.
To remove an electron requires energy.
Ionization energy is the energy required to remove the least tightly bound (or outermost) electron from an atom.
What is the trend of ionization energy?
Decreases from top to bottom
-INcreases from left to right
What is electronegativity?
Electronegativity is the tendency of an element to attract
electrons in a bond.
Therefore, elements that want to gain electrons will have
higher electronegativity.
What is the trend for electroegativity?
Same for ionization energy
Decreases from top to bottom
-INcreases from left to right
