Chemistry 1-7: Periodic Trends

Periodic Trends

Multiple Choice

What is the system of electrons surrounding the nucleus of an atom?

• valence electrons

• nucleus

• electron bunch

• electron cloud

Multiple Choice

How many groups/families are on the periodic table?

• 15

• 16

• 17

• 18

Multiple Choice

What group number are the halogens?

• 18

• 1

• 2

• 17

Multiple Choice

What determines an element's atomic number?

• When it was Discovered

• Number of Neutrons

• It's Mass

• The Number of electrons/Protons

Multiple Choice

What is the term for the vertical columns of the periodic table?

• Groups

• Stacks

• Periods

• Clans

Multiple Choice

What is the term for the horizontal rows on the periodic table?

• Period

• Group

• Family

• Stripe

Multiple Choice

These elements are the most reactive of the non-metals

• Alkali Metals

• Alkaline Earth Metals

• Noble Gases

• Halogens

Multiple Choice

What is the atomic mass number?

• the number of protons in the nucleus

• the number of protons and neutrons in the nucleus

• the number of neutrons in the nucleus

• the number of protons and electrons in the atom

Multiple Choice

If an atom has 12 positively charged subatomic particles, which of the following must it also have to be considered a neutral atom?

• 12 neutrons
• 12 electrons
• 12 protons
• 24 protons and neutrons

Multiple Choice

Silicon is a semiconductor and has properties of both metals and nonmetals. What type of element is Silicon? 

• Metal
• Nonmetal
• Metalloid
• Pretty

Multiple Choice

What group number are the noble gases?

• 17

• 18

• 14

• 15

Multiple Choice

What is the name of group number 2?

• transition metals

• halogens

• metaloids

• alkaline earth metals

• Alkali Metals

Multiple Choice

What is the center of an atom containing protons and neutrons?

• nucleus

• neutron

• proton

• electron cloud

Lesson Objectives

• Describe the most important trends on the periodic table and how they change

Periodic Trends

• As you move across the periodic table, you see trends in how certain properties change as you move across a period or up and down a group

• The properties we are going to focus on

  • Atomic Radius

  • Ion size

  • Ionization Energy

  • Electron Affinity​

Atomic Radius

• ​The size of an atom is defined by the edge of its orbital

  • ​Fuzzy boundary, varies in different conditions

• ​A more specific form of measurement helps get a general size

  • ​Atomic Radius: 1/2 the distance between the nuclei of identical atoms that are bonded together

Atomic Radius on the Periodic Table

• ​Atoms get smaller as you move across a period Left to right

  • ​Caused by an increasing positive charge of the nucleus

• ​​In general, Atomic Radii increases as you move down a group

Ions

• Ion: an atom or group of atoms that has a positive or negative charge

  • Neutral atoms can either lose or gain electrons to change their charge

    • If a metal atom loses an electron, it becomes a more positive cation

      • The radius of a cation is smaller than a neutral atom, because it has lost an ion

    • If a nonmetal gains an electron, it becomes a more negative anion

      • The radius of anion is larger than the neutral atom because it gained an electron

Ionization Energy (I)

• Ionization energy is the energy required to remove the outermost electron from the ground state of a gaseous atom

  • Is directly related to the size of the atom due to Coulomb's law​

    • Small atoms have high ionization energies and large atoms have low ionization energies

Successive Ionization Energy

• More than one electron can be removed from an atom to form an ion

  • As you remove more and more electrons, the ionization energy required gets higher and higher

    • I₁ < I₂ <I₃ ............

Multiple Choice

The atomic radii is the distance between What?

• The electrons in an atom of an element

• 1/2 the distance between the nuclei of bonded identical atoms 

• two atoms that repel each other

Multiple Choice

The atomic radii ____________ as you move left to right across a period on the periodic table

• Increases

• Decreases

Multiple Choice

How does the atomic Radii change as you move down a group on the periodic Table?

• It increases

• It Decreases

• It stays the same

• It changes randomly

Electron Affinity

• Electron Affinity: The energy change that happens when an atom gains an electron

  • For most atoms, energy is released

    • A higher electron affinity=more energy released​

  • The trend is not quite a consistent as other trend

Common Ion Charges in Representative Elements

• For some groups all the Elements in it form ions with the same charge

  • Group 1: +1

  • Group 2: +2

  • Group 15: -3

  • Group 16: -2

  • Group 17: -1​

Connecting the Trends

Multiple Choice

How does ionization energy change as it moves left to right across a period?

• It Increases

• It Decreases

• It stays the same

• It changes randomly

Multiple Choice

How does Ionization energy change as it moves Down a Group?

• It Increases

• It Decreases

• It stays the same

• There is no correlation

Multiple Choice

How does Electron affinity change going left to right across a period?

• It Increases

• It Decreases

• It stays the same

• There is no correlation

Categorize

Options (14)

Sodium

Potassium

Calcium

Strontium

Barium

Magnesium

Fluorine

Chlorine

Bromine

Iodine

Oxygen

Sulfur

Selenium

Lithium

Sort the Elements by the type of ionic charge they will form.

+1 Ion Charge

+2 Ion Charge

-1 Ion Charge

-2 Ion Charge