Periodic Trends

Periodic Trends

Using the periodic table to understand how certain trends work and be able to make predictions on how certain elements may react.

Summary

Today we will go over the different trends of the periodic table and how this correlates to properties of the elements based on their position (period and group)

Prior Knowledge

Before going forward, we need to remember what we have learned. Click on the elements icon below to refresh on what a group and period are. Both are important for trends

Groups!!

Remember each group of elements are grouped by their chemical properties. They all have the same number of valence electrons For example...... Both Neon and Argon are is group 18 therefore they have 8 valence electrons. Because they have the same full valence shell they are noble gases.

Atomic Radius (Size)

Energy levels (Shells) are like onions (Atomic Size)

1st Energy level (Period 1)

2nd Energy level (Period 2)

3rd Energy Level (Period 3)

4th Energy Level (Period 4)

5th Energy Level (5th period)

Question Time

periods (Opposites attract) (Atomic Size)

• Like magnets, the electrons and protons are attracted to one another
• When moving from left to right , the nuclear charge gets larger making the atom smaller.
• More protons = smaller in size within a period
• Hover over the magnet to see the trend

Interactive question

Take a moment to think about why calcium is larger than Arsenic?

ions

Cations! (Loses electrons) More protons than electrons = stronger attraction This will make the cation smaller than a nuetral atom

Anions! (Gains electrons) More electrons than protons = electrons repulsion. This will cause the anion to be larger than a neutral atom.

Ionization energy

Ionization Energy

• Minimal energy need to remove an electron from an atom NOT A PROTON OR NEUTRON

Ionization Trend

Look at the chart to the right. What do you notice?

What type of elements are on top, need the most energy.

What type of elements are in green needing less energy?

Groups are All about the distance

• Depending on energy levels (shells)
• less shells =more energy to remove an electron (fighting attraction from nucleaus)
• more shells = less energy to remove an electron (weakened attraction to the nucleus)

Energy increases when going up the group

Interactive Question

Periods are all about the charge

More energy is needed to remove an electron across the period BECAUSE there is a higher nuclear charge from left to right

Electronegativity

Electrobegativity

Electroneagativity is the ability to attract an electron Metals want to lose electrons which is why they have low EN Nonmetals want to gain so they have a high EN

Interactive question

Reactivity

Reactivity Trend

Reactivity is an element's tendency to undergo a chemical reaction, and its trend on the periodic table varies for metals and nonmetals.

• Metals want to lose valence electrons
• Nonmetals want to gain valence electrons

Because of this their trends for reactivity go in opposite directions

nonmetals

Metals

Nonmetals want to gain electrons . This means that the side with the most electrons (but not a full 8) and fewer shells are the most reactive

Metals want to get rid of their electrons . There for the side with the fewer valence electrons and greater shells are more reactive

Interactive question

Interactive question

Before leaving today, compare two of the trends discussed and write down how group and periods affect those specific trends