The Periodic Table and Atomic Mass (Learning Objectives)

Periodic table has a number of ____ elements first published by ___ ___ in 1869. They are arranged by atomic ___. Vertical ____ representing groups and rows representing ___.

118; Dmitri Mendeleev; number; columns; periods

Be familiar with the first three periods. Try to name them

H, He, Li, Be (Beryllium) B, C, N, O, F, Ne, Na, Mg, Al (Aluminum), Si (Silicon), P (Phosphorous), S (Sulfur), Cl, Ar.

Group Classification:

Main group/representative: ___, ___, ___---___

Transition Metals: ___-___

Inner transition metals:

1, 2, 13-18
3-12
Lanthanides and Actinides

Elements within the same group have the same number of ___ in their valence shells, meaning they have similar chemical ____ and ____ types. (Not counting groups with a mix of metals/nonmetals)

electrons, properties, bonding

Group 1 is called the ___ metals. They are ___ (easy to cut), and look ____ that react violently with ___

alkali, soft, silvery, water

Group 2 is known as the ___ ___ ___. They are ___ reactive to water than group 1, they look ___, and reacts with ___

alkaline earth metals, less, shiny, O2

Group 16 is called the ___.

Group 17 are called ___. They are very ___ and ___ (eat away/damage)

Chalcogens

Halogens, reactive, corrosive

Group 18 are called the ___ ___. They are ____ and have very low chemical ____

noble gases, colorless, reactivity

Metals are typically ____ and ___-looking, have ___ mp/bp, and ___ conductor of heat/electricity.

hard, metallic, high, good

Nonmetals are typically ___, have ___ mp/bp, and are ___ conductors of heat/electricity

soft, low, poor

Metalloids are ___-___ properties.

In-between

Metallic trend is how easy an atom will give up an ____. Their metallic character will ___ down a group and ___ down a row. (Extra points, explain why this is)

electron, increase, decrease

Increase down a group: they have bigger shells (further electrons), so easy to take away

Decrease down a row: More protons in a nucleus, same valence shell, so harder to take

Atomic mass: 1 amu (aka ___) is exactly ___ of a carbon-12 atom.

Da, 1/12

1 amu = ____ kg

1.661 × 10^(-27)

1 amu = ____ g

1.661 × 10^(-24)

Atomic mass refers to the mass of a single atom. But on the periodic table, it is the ___ ___ for all naturally occurring ___ of an element.

weighted average, isotopes

(Need to do the math for this one)

Carbon has 2 isotopes: ¹²C (12.000 amu, 98.89% abundance) and ¹³C (13.003 amu, 1.11% abundance). Find the average atomic mass

(12.000 amu x 0.9889) + (13.003 amu x 0.0111) = 12.011 amu

Natural carbon is composed of two isotopes, ¹²C (12.000 amu) and ¹³C (13.003 amu). The average atomic mass of carbon is 12.011 amu. Calculate the percent abundance of each isotope.

12.000x + 13.003y = 12.011 amu
x+y=1

then solve by substitution

1 Mole = ____ atoms/molecules/ions. This hidden number is also called ___’s number

6.022 × 10^(23); Avogadro’s

If H2O is roughly 18 amu, then that means it’s also 18 ___/___ so for every 18 ___, there is 1 mole of H2O, which means there are ____ molecules of H2O. However, there are ___ moles of H and ___ mole of O.

g/mol, grams, 6.022 × 10^(23), 2, 1

Molecular mass is found by ___ all amus on the periodic table. For instance, in H2O, what would the molecular mass be?

adding

2 H’s, 1 O —→ 2(1amu) + 16 amu = 18amu

Molar mass is found by calculating the ____ mass and then just changing atomic mass units to ___. For instance, what is 18 amu in molar mass?

molecular, g/mole, 18g/mole

Proof that 1 amu per particle = 1 grams per mole (just review, no need to know it)

If I had 36 grams of H2O, how many moles do I have?

Molecular mass = 18 amu = 18 g / mole

36 grams divided by 18 g/mole = 2.0 moles of H2O

If I had 2.0 moles of H2O, how many particles do I have?

Avogadro’s number: 6.022 × 10^(23) particles / mole

2.0 moles multiplied by 6.022 × 10^(23) particles / mole = 12.0 × 10^(23) = 1.2 × 10^(24) molecules of H2O

If I had 3.6 × 10^(23) particles of O, how many moles do I have?

Avogadro’s number: 6.022 × 10^(23) particles per mole

3.6 × 10^(23) / 6.022 × 10^(23) = 0.498 Moles

If I had 0.498 moles of O, what is its mass in grams?

O = 16 amu = 16 g / mol

0.498 moles (16 g / mol) = 7.97 g

To go from mass to moles, you take the mass of the substance given in ___, find the ____ mass of the substance in amu, convert into ____, and then ___ the mass given by the conversion.

Ex: 16g of O is how many moles?

grams, molecular, g/mol, divide

16g is given, O = 16amu = 16 g/mol —> 16g / 16 g/mol = 1 mole.

On the periodic table, metals are to the ___, nonmetals are to the ___, and metalloids are along a ___

left, right, zigzag (staircase)

Periodicity of the periodic table:

Repeating ___ of element ____ when ordered by ___ ___. Properties include ____ character, atomic ___, and ____

patterns, properties, atomic number, metallic, radius (decreases right to left and increases from top to bottom), electronegativity (increases right to left and bottom to top)