Chemistry Test - Periodic Trends Flashcards
What information is used to organize the modern periodic table?
- Atomic number
- Valence shells
- Element properties
How does atomic mass relate to the atomic number?
Atomic number = mass - neutrons
What does periodic mean?
Periodic means a repeating pattern.
What properties are common to the left side of the periodic table you made? What properties are common to the right side of the periodic table you made?
Left: soft, shiny metals that react with oxygen and water.
Right: Non-Metals and gases.
Where are the Akali Metals?
First Column
Where are the Alkaline Earth Metals?
Second Column
Where are the Halogens?
Second column on the right side (F, Cl. Br, I)
Where are the Noble gases?
Furthest right column.
Which element in each of the following groups has the largest atomic radius? (Halogens, Alkali Metals, Noble Gases)
a) Halogens - Iodine
b) Alkali Metals - Francium
c) Noble Gases - Radon
Arrange the following atoms in order of increasing atomic radius (smallest to largest): K, Rb, Cs, F, Li, C
Li, C, F
K, Rb, Cs
Atomic Radius Definition:
A measurement of the size of an ion, usually expressed in picometers (pm); the distance from the centre of an ion to the outermost (valence) electrons.
Across a Row Atomic Radius Increases:
From right to left.
Across a Row Atomic Radius Decreases:
From left to right
Atomic Radius Row Example for Smallest Radius: Li or F?
F is the smallest as it is towards the right side of the periodic table. Atoms further on the right of the periodic table have more protons to attract the electrons in. Therefore, making the atomic radius smaller as the electrons are pulled closer to the nucleus.
Atomic Radius Row Example for Biggest Radius: S or Mg?
Mg is the biggest radius as it is towards the left side of the periodic table. Atomics further on the left of the periodic table have fewer protons to attract the electrons in. Therefore, making the atomic radius bigger as the electrons are further away from the nucleus.
Template for Atomic Radius Row examples:
( ) is the (smallest/biggest) as it is towards the (right/left) of the periodic table. Atoms further on the (right/left) of the periodic table have (more/fewer) protons to attract electrons in. Therefore, making the atomic radius (smaller/bigger) as the electrons are (pulled closer to/further away from) the nucleus.
Column Atomic Radius Increases:
As you go down a column.
Column Atomic Radius Decreases:
As you go up a column.
Atomic Radius Column Example for Smallest Radius: Sr or Be?
Be is the smallest as it is higher up in the column. Atoms higher up have fewer shells and therefore, are smaller.
Atomic Radius Column Example for Biggest Radius: O or Se?
Se is the biggest as It is lower down in the column. Atoms lower down have more shells and therefore, are bigger.
Template for Atomic Radius Column:
( ) is the (smallest/biggest) as it is (higher up/lower down) in the column. Atoms (higher up/lower down) have (fewer/more) shells and therefore, are (smaller/bigger).
Ionization Energy Definition:
The quantity of energy required to remove an electron from an atom or ion in the gaseous state.
Across a Row Ionization Energy Increases:
To the right.
Across a Row Ionization Energy Decreases:
To the left.
Ionization Energy Row Example for Lowest I.E.: Na or P?
Na is further to the left so it has less protons than P. Therefore, electrons are attracted less strongly and Ionization Energy is lower.
Ionization Energy Row Example for Highest I.E.: Be or O?
O is further to the right so it has more protons than Be. Therefore, electrons are attracted more strongly and Ionization Energy is higher.
Template for Ionization Energy Row:
( ) is further to the (left/right) so it has (less/more) protons than ( ). Therefore, electrons are attracted (more/less) strongly and Ionization Energy is (lower/higher).
Column Ionization Energy Increases:
Up a column.
Column Ionization Energy Decreases:
Down a column.
Ionization Energy Column Examples for Highest I.E.: Sr or Be?
Be is higher in the column, giving it a smaller radius and thus, less inner shielding electrons. This makes the energy valence electrons closer to the protons, with less electrons in the way. Therefore, creating a higher attraction, and a higher Ionization Energy, making the electrons harder to remove.
Ionization Energy Column Example for Lowest I.E.: O or Se?
Se is lower in the column, giving it a larger radius and thus, more inner shielding electrons. This makes the energy valence electrons further away from the protons, with more electrons in the way, Therefore, creating a lower attraction, and a lower Ionization Energy, making the electrons easier to remove.
Template for Ionization Energy Column:
( ) is (lower/higher) in the column, giving it a (larger/smaller) radius and thus, (more/less) inner shielding electrons. This makes the energy valence electrons (closer to/further away from) the protons, with (more/less) electrons in the way. Therefore, creating a (lower/higher) attraction, and a (lower/higher) Ionization Energy making the electrons (easier/harder) to remove.
? is colourless in an acid and pink in a base
Phelophalen is colourless in an acid and pink in a base
? react by losing electrons
Metals react by losing electrons
? is the energy required to remove the electron
Ionization energy is the energy required to remove the electron
Anything that lowers the ? allows the electron to be removed more easily and gives it a bigger reaction
Anything that lowers the ionization energy allows the electron to be removed more easily and gives it a bigger reaction
Write out the full reaction for either Li or K, or Rb, or Cs as was done in the example with Na in the video.
Sodium + Water -> Sodium Hydroxide + Hydrogen Gas
2Na(s) + 2HOH(l) -> 2NaOH(aq) + 1H2(g)
Potassium + Water -> Potassium Hydroxide + Hydrogen Gas
2K(s) + 2HOH(l) -> 2KOH(aq) + 1H2(g)
The word format for column 1 (Alkali metals) reactions with water?
Alkali Metal + Water -> Alkali Metal Hydroxide + Hydrogen Gas
The elemental format for column 1 (Alkali metals) reactions with water?
2Alkali Metal Symbol(s) + 2HOH(l) -> 2Alkali Metal Symbol OH(aq) + 1H2(g)
What left each of the metals that caused the reaction?
Electrons.
Use the ideas of ionization energy and shells to explain why Li was the least reactive, Na was more reactive and K was the most reactive of the elements that we tested in class. [4]
Hints
a) How many shells does Li have and does this make the radius Big or medium or small?
b) Does this put the valence electron close to or far away from the protons in the nucleus?
c) Are there many inner shielding electrons between the valence electron and the nucleus? What does this do to the attraction between the Valence and the nucleus?
d) What do the above do to the ionization energy and the reactivity?
- Lithium has the smallest number of shells and therefore the smallest radius.
- This means the valence electron is the closest to the protons and is attracted more strongly.
- Lithium also has the fewest inner shielding electrons blocking the valence electron from seeing the protons.
- Therefore the valence electron is attracted more.
For both reasons, the electron is harder to remove, and the Ionization energy is highest. Since metals react by losing electrons, Li is the least reactive.