Introduction to the Periodic Table

Multiple Select

Based on the organization of the periodic table, which of the following statements are true?

• Periods are horizontal rows.

• Groups are vertical columns.

• Elements in the same period have the same number of valence electrons.

• Elements in the same group have similar properties.

Multiple Choice

Which element has the greatest atomic mass?

• Lithium

• Sodium

• Potassium

• Rubidium

Multiple Choice

Which group of elements contains both metals and nonmetals?

• Group 1

• Group 2

• Group 13

• Group 17

Multiple Choice

Which of the following is NOT a property of metals?

• Shiny

• Poor conductor

• Malleable

• Ductile

Multiple Select

Which of the following statements about nonmetals is/are correct?

• They are poor conductors.

• They are usually shiny.

• They tend to be less reactive than metals.

• Their solids are brittle.

Multiple Choice

What is the most common example of a metalloid and where is it commonly found?

• Silicon, in sand and glass

• Carbon, in living organisms

• Sulfur, in minerals

• Gold, in jewelry

Multiple Choice

Which is not a property of nonmetals?

• Brittle.

• Non Malleable.

• High conductivity.

• Most are gases at room temperature

​-The closer an element is to having the same number of electrons as a noble gas, the more reactive the element is.
-The alkali metals are very reactive because they are just one electron away from the noble gases.
-The halogens are also very reactive because they are also one electron away from the noble gases.

Multiple Choice

Which nonmetal is probably the most reactive?

• Nitrogen

• Oxygen

• Fluorine

• Neon

Periodic Trends

Atomic Radius, Ionization Energy, Electron Affinity, and Electronegativity

Atomic Radius

• One-half the distance between the nuclei of identical atoms that are bonded together.

• Measure the distance between the nuclei of two identical atoms bonded together and divide the distance by 2.

Atomic Radius

Compare the size of each atom in the picture to the right. Do you notice any trends?

Multiple Choice

Based on the image on the last slide. As you go across a period, does the atomic radius get smaller or larger?

• Smaller

• Larger

• Stays the same

Atomic Radius

• As you go across the period (row) Atomic Radius decreases.

• This is caused by an increasing positive charge in the nucleus.

• Electrons are on the same energy level going across the period, but more protons are pulling electrons in closer. This results in a smaller atomic radius.

Atomic Radius

• As you go down a group (column) Atomic Radius increases

• The number of electron shells increase as you move down the periodic table.

• This results in a larger atomic radius because the nucleus has less pull on the outer shell of electrons.

Multiple Choice

Put these elements in order of INCREASING atomic radius.

Li, O, C, F

• O, C, F, Li

• F, O, C, Li

• Li, C, O, F

• C, F, Li, O

Multiple Choice

Put these elements in order of DECREASING atomic radius.

Ca, Be, Ba, Sr

• Sr, Ba, Be, Ca

• Be, Ca, Sr, Ba

• Ba, Sr, Ca, Be

• Ca, Be, Ba, Sr

Ionization Energy

• The energy required to remove one electron from the outer shell of a neutral atom.

• This is the energy needed to form an ion.

• When ionization energy is high it is harder to remove that electron.

Multiple Choice

Which elements do you think will have a low ionization energy and lose electrons more readily?

• elements that form anions (negative charge)

• Elements that form cations (positive charge)

• Transition metals

Ionization Energy

• Moving across a period, ionization energy increases.

• Group one has a low ionization energy and has a high reactivity

• Group 18 has a high ionization energy and are unreactive.

• Caused by an increasing positive charge in the nucleus, attracting electrons more strongly.

Ionization Energy

• decreases as you move down the periodic table.

• Elements with larger atomic radius have less pull on their electrons in the outer shell and tend to give them up.

Electron Affinity

• The energy change that occurs when a neutral atom gains an electron.

• energy changes that are more negative have a higher electron affinity.

Electron Affinity

• As you move across the period table, electron affinities generally become more negative.

• There are some exceptions to this rule.

Electronegativity

• Measures the ability of an atom in a chemical compound to attract electrons from another atom in the compound.

• Think about what elements attract electrons.

• The highest value is 4.0 and fluorine is the most electronegative element.

Electronegativity

• Increases as you move across the periodic table.

• Group 1 and 2 metals are the least electronegative elements and tend to lose electrons when forming ions.

• Nitrogen, oxygen, and halogens are the most electronegative and strongly attract electrons when in compounds.

• Decreases or stays the same moving down a group.

Multiple Choice

What elements have the highest Electronegativity?

• Halogens (group 17)

• Alkali Metals (Group 1)

• Alkaline-earth Metals (group 2)

• Noble gases (group 18)