Table of contents

Skip topic navigation

1. The Chemical World9m

The Scientific Method
9m

2. Measurement and Problem Solving2h 19m

Scientific Notation
13m

SI Units (Simplified)
5m

Metric Prefixes
24m

Significant Figures (Simplified)
11m

Significant Figures: Precision in Measurements
7m

Significant Figures: In Calculations
14m

Conversion Factors (Simplified)
15m

Dimensional Analysis
24m

Density
13m

Density of Non-Geometric Objects
9m

3. Matter and Energy2h 15m

Classification of Matter
18m

States of Matter
8m

Physical & Chemical Changes
19m

Chemical Properties
8m

Physical Properties
5m

Temperature (Simplified)
9m

Law of Conservation of Mass
5m

Nature of Energy
5m

First Law of Thermodynamics
7m

Endothermic & Exothermic Reactions
7m

Heat Capacity
17m

Thermal Equilibrium (Simplified)
8m

Intensive vs. Extensive Properties
13m

4. Atoms and Elements2h 33m

The Atom (Simplified)
9m

Subatomic Particles (Simplified)
11m

Isotopes
17m

Ions (Simplified)
22m

Atomic Mass (Simplified)
17m

Periodic Table: Element Symbols
6m

Periodic Table: Classifications
11m

Periodic Table: Group Names
8m

Periodic Table: Representative Elements & Transition Metals
7m

Periodic Table: Phases (Simplified)
8m

Periodic Table: Main Group Element Charges
12m

Atomic Theory
9m

Rutherford Gold Foil Experiment
9m

5. Molecules and Compounds1h 50m

Law of Definite Proportions
9m

Periodic Table: Elemental Forms (Simplified)
6m

Naming Monoatomic Cations
6m

Naming Monoatomic Anions
5m

Polyatomic Ions
25m

Naming Ionic Compounds
11m

Writing Formula Units of Ionic Compounds
7m

Naming Acids
18m

Naming Binary Molecular Compounds
6m

Molecular Models
4m

Calculating Molar Mass
9m

6. Chemical Composition1h 23m

Empirical Formula
21m

Molecular Formula
20m

Mole Concept
37m

Mass Percent
4m

7. Chemical Reactions1h 43m

Chemical Reaction: Chemical Change
5m

Balancing Chemical Equations (Simplified)
13m

Solubility Rules
16m

Electrolytes (Simplified)
13m

Molecular Equations
18m

Types of Chemical Reactions
12m

Complete Ionic Equations
18m

Gas Evolution Equations (Simplified)
6m

8. Quantities in Chemical Reactions1h 8m

Stoichiometry
23m

Limiting Reagent
12m

Percent Yield
20m

Thermochemical Equations
12m

9. Electrons in Atoms and the Periodic Table2h 32m

Wavelength and Frequency (Simplified)
5m

Electromagnetic Spectrum (Simplified)
11m

Bohr Model (Simplified)
9m

Emission Spectrum (Simplified)
3m

Electronic Structure
4m

Electronic Structure: Shells
5m

Electronic Structure: Subshells
4m

Electronic Structure: Orbitals
11m

Electronic Structure: Electron Spin
3m

Electronic Structure: Number of Electrons
4m

The Electron Configuration (Simplified)
20m

The Electron Configuration: Condensed
4m

Ions and the Octet Rule
9m

Valence Electrons of Elements (Simplified)
5m

Periodic Trend: Metallic Character
4m

Periodic Trend: Atomic Radius (Simplified)
7m

Periodic Trend: Ionization Energy (Simplified)
9m

Periodic Trend: Electron Affinity (Simplified)
7m

Electron Arrangements
5m

The Electron Configuration: Exceptions (Simplified)
12m

10. Chemical Bonding2h 10m

Lewis Dot Symbols (Simplified)
7m

Ionic Bonding
6m

Covalent Bonds
6m

Lewis Dot Structures: Neutral Compounds (Simplified)
8m

Bonding Preferences
6m

Multiple Bonds
4m

Lewis Dot Structures: Multiple Bonds
10m

Lewis Dot Structures: Ions (Simplified)
8m

Lewis Dot Structures: Exceptions (Simplified)
12m

Resonance Structures (Simplified)
5m

Valence Shell Electron Pair Repulsion Theory (Simplified)
4m

Electron Geometry (Simplified)
7m

Molecular Geometry (Simplified)
9m

Bond Angles (Simplified)
11m

Dipole Moment (Simplified)
14m

Molecular Polarity (Simplified)
7m

11 Gases2h 7m

Pressure Units
6m

Kinetic Molecular Theory
14m

The Ideal Gas Law
18m

The Ideal Gas Law Derivations
9m

The Ideal Gas Law Applications
6m

Chemistry Gas Laws
13m

Chemistry Gas Laws: Combined Gas Law
12m

Standard Temperature and Pressure
14m

Dalton's Law: Partial Pressure (Simplified)
13m

Gas Stoichiometry
19m

12. Liquids, Solids, and Intermolecular Forces1h 11m

Intermolecular Forces (Simplified)
19m

Intermolecular Forces and Physical Properties
11m

Atomic, Ionic and Molecular Solids
10m

Heating and Cooling Curves
30m

13. Solutions3h 1m

Solutions
6m

Solubility and Intermolecular Forces
18m

Solutions: Mass Percent
6m

Molarity
18m

Osmolarity
15m

Solubility: Temperature Effect
8m

Intro to Henry's Law
4m

Dilutions
13m

Solution Stoichiometry
14m

Molality
15m

The Colligative Properties
15m

Boiling Point Elevation
16m

Freezing Point Depression
9m

Osmosis
16m

14. Acids and Bases2h 14m

Acid-Base Introduction
11m

Arrhenius Acid and Base
6m

Bronsted Lowry Acid and Base
18m

Acid and Base Strength
17m

The pH Scale
19m

Auto-Ionization
5m

pH of Strong Acids & Bases
11m

Acid-Base Reactions
7m

Buffers
25m

Strong Acid Strong Base Titrations (Simplified)
10m

15. Chemical Equilibrium1h 27m

Rate of Reaction
11m

Energy Diagrams
12m

Chemical Equilibrium
7m

The Equilibrium Constant
14m

Le Chatelier's Principle
23m

Solubility Product Constant (Ksp)
17m

16. Oxidation and Reduction1h 33m

Calculate Oxidation Numbers
15m

Redox Reactions
17m

Spontaneous Redox Reactions
8m

Balancing Redox Reactions: Acidic Solutions
17m

Balancing Redox Reactions: Basic Solutions
17m

Galvanic Cell (Simplified)
16m

17. Radioactivity and Nuclear Chemistry53m

Types of Radiation
5m

Alpha Decay
8m

Beta Decay
11m

Gamma Emission
6m

Positron Emission
5m

Radioactive Half-Life
8m

Measuring Radioactivity
7m

4. Atoms and Elements

Isotopes

Introduction to Chemistry

4. Atoms and Elements

Isotopes

Previous problemNext problem

Struggling with Introduction to Chemistry?

Join thousands of students who trust us to help them ace their exams!Watch the first video

Multiple Choice

A period 5 transition metal has 51 neutrons. If the element is yttrium, what is the mass number of this isotope? (Atomic number of Y is $39$ .)

51

39

129

90

Previous problemNext problem

4:36m

Watch next

Master Isotopes with a bite sized video explanation from Jules

Start learning

Isotopes practice set

Problem sets built by lead tutors

Expert video explanations

Go to Practice

Download the Mobile app

Accessibility

Privacy

Do not sell my personal information

Struggling with Introduction to Chemistry?

A period 5 transition metal has 51 neutrons. If the element is yttrium, what is the mass number of this isotope? (Atomic number of Y is 39.)

Watch next

Isotopes practice set

A period 5 transition metal has 51 neutrons. If the element is yttrium, what is the mass number of this isotope? (Atomic number of Y is $39$ .)