AP Chemistry Unit 1 Video Quizzes

What subatomic particles contribute to the mass of an atom?

Protons and neutrons

What defines the identity of an atom?

The number of positively charged protons

Why is the atomic mass of an element reported on the periodic table as a decimal and not a whole number?

It's a weighted average of all the isotopic relative abundance

What is the molar mass of silver (Ag)?

107.87 g/mol

How many moles of silver (Ag) are in a 3.6 g ring?

0.033 mol Ag

A mole is a quantity and a very helpful counting unit for chemists. How many particles does a mole equal?

1 mole = 6.022 x 10²³ particles

Tartaric acid, used to give sour candies their characteristic sour taste, has an empirical formula of C₂H₃O₃ and a molar mass of 150.1 g/mol. What is the molecular formula of tartaric acid?

C₄H₆O₆

Determine the chemical formula of the mineral forsterite which contains 34.55% Mg, 19.96% Si, and 45.48% O by mass.

Mg₂SiO₄

A compound has an empirical formula of P₂O₅. What is the molecular formula of this compound if it's molar mass is 284 g/mol?

P₄O₁₀

All of the following are mixtures except

Sugar

There are two types of pure substances

Elements and compounds.

A 54 g sample of ocean water contains 0.75 g of Na⁺ ions. What percent of the sample is salt, NaCl?

3.5% NaCl

What is the noble gas configuration of tin (Sn)?

[Kr] 5s² 4d¹⁰ 5p²

What is the correct orbital diagram for Fluorine?

↿⇂ ↿⇂ ↿⇂ ↿⇂ ↿

What force allows the electrons to stay within the electron cloud?

The attractive pull from the positively charged nucleus

Why do electrons have such a complex arrangement within the electron cloud?

To balance the attractive force of the nucleus with the repulsive force of the electrons

Why is magnesium's 3^rd ionization energy so much larger than its 1^stor 2^nd ionization energies?

 

1st Ionization Energy	2nd Ionization Energy	3rd Ionization Energy
735	1445	7730

It takes more energy to remove core electrons than it does to remove valence electrons

What is the trend across a row for Z_eff, atomic radii, and ionization energy?

Z_eff increases; atomic radii decreases; ionization energy increases

Why does oxygen have a slightly lower ionization energy than nitrogen even though the trend has an overall increase across the row?

Oxygen prefers to lose the paired electron in its p-subshell to reduce electron repulsion within the orbital.

As layers of core electrons increase down a column, what happens to Z_eff?

Z_eff gets weaker making it harder to attract valence electrons

As protons increase across a row, what happens to Z_eff?

Z_eff gets stronger allowing the nucleus to pull the electrons in closer

Arrange the atoms in order of decreasing electronegativity.

 

F > Cl > Br > I