Ionization Energy Information Page

Broad definition of what we are considering

We focused on videos that primarily addressed conceptual understanding related to ionization energy, both trends in first ionization energy and trends in successive ionization energies.

Johnstone's Triangle Elements

Ionization Energy Specific Criteria

Element	Examples
Macroscopic	General Definition for Macro: things we can see (observations) OR specific measurements. Ionization energy values explicitly provided (or interpretable). Visual examples of relative reactivity of alkali metals.
Symbolic	General Definition for Symbolic: standardized, discipline-specific short-form representations that efficiently communicate significant information. It is a universal shorthand that bridges the macroscopic and particulate levels. The periodic table (PT) is a symbolic representation. Chemical equations showing neutral atom losing an electron to form an ion. Chemical equations for successive removal of electrons. Graph that shows trends in IE.
Particulate	General Definition for Particulate: visual model that helps “visualize” arrangement, movement, interaction, or composition of matter as it relates to the concept of interest. Particle depictions showing position of electrons, valence electrons, electron shielding.
Connection between levels	Videos should make explicit connections between two or more levels for this to be coded as present. For example, they could show the chemical reaction along with a particle level drawing or animation. For example, connecting graph of first IEs to the periodic table (macro to symbolic) - must explicitly connect to table; connect Bohr models of atoms to IE values (e.g., why Li has a lower IE than Ne). Makes connection between macroscopic (IE data), particulate (Bohr Model) and symbolic (e^- configurations). Makes connection between macroscopic (graph with real IE data), particulate (Bohr Model) and symbolic (PT and e^- configuration boxes).

Core Ideas

Energy	Atomic/Molecular Structure & Properties
Core Ideas Elements
Energy changes are either the cause or the consequence of change in chemical systems, which can be considered on different scales and can be accounted for by the conservation of the total energy of the system of interest and the surroundings.	The macroscopic physical and chemical properties of a substance are determined by the three-dimensional structure, the distribution of electron density, and the nature and extent of noncovalent interactions between the particles.
Video needs to include: Trend in first ionization energies must include that valence electrons are attracted to the nucleus of the atom and that the strength of this attraction depends on the number of protons in the nucleus and/or the distance from the nucleus. The stronger the force of attraction, the higher the ionization energy. OR Successive ionization energies always increase in value due to the greater attraction to the nucleus. A very large jump occurs when ionization proceeds from one shell to a more interior shell.	Video needs to include: A description of how ionization energy is connected to macroscopic or chemical properties, such as the relative reactivity of substances (e.g., alkali metals) or the common ions formed by different elements. For example, why metals tend to form positive ions while nonmetals tend to form negative ions.
	Note: some macroscopic context is also present at the very start of the video.

Casual Mechanistic Reasoning

Must have both How and Why?

Option 1: What causes ionization energies to get larger going across the periodic table?

How: As we go across the periodic table, atoms gain an additional proton in the nucleus and electrons to the same electron shell (must address this explicitly). This will increase the attractive force (Z or Z_eff) between the valence electrons and the nucleus.

Why: Increased attractive forces between the outermost electron and the nucleus will mean that the force of attraction will be stronger and so will require more energy to be removed from the atom. The answer should address the concept of Coulomb’s Law, though specifically naming it is not required.

How: As we go across the periodic table, atoms will get successively smaller. This will increase the attractive force (Z or Z_eff) between the electrons and the protons.

Why: The decreased distance between the outermost electron and the nucleus means that the force of attraction is stronger and thus will require more energy to be removed from the atom. The answer should address the concept of Coulomb’s Law, though specifically naming it is not required.

Option 2: What causes ionization energies to get smaller going down a family in the periodic table? How: As we go down a family in the periodic table, atoms gain an additional electron shells which are further from the nucleus. Why: As the size of the atom increases through additional shells (and protons), and because (Z_eff remains constant OR explicitly addressing the inverse squared relationship between attractive force and distance (one of these MUST be explicitly addressed)), the force of attraction between the outermost electron and the nucleus will decrease, meaning that less energy will be needed to remove the electron from the atom. The answer should address the concept of Coulomb’s Law, though specifically naming it is not required.

Option 3: What causes successive ionization energies to increase?

How: Removing successive electrons requires removing electrons from ions that are already positive and in some cases electrons from a different electrons shell.

Why: The outermost electrons will experience an increased force of attraction as the positive charge on the ion increases, thus requiring more energy to remove electrons from a lower shell as these electrons are closer to the nucleus and experience a notably greater force of attraction.

Option 4: What causes exceptions to the general trend of ionization energies (specifically group 2 vs 3 and 15 vs 16)? How: The electrons being removed from group 13 vs. 2 are in different subshells and in 15 vs. 16 the electrons have been paired. Why: p orbitals are higher in energy than the s orbitals in the same subshell, so less energy is required to remove that electron than might otherwise have been anticipated. This difference results in group 13 having a lower first ionization energy than the group 2 elements in the same period. For group 15 vs. 16, in the case of group 16, the last electron is paired up with another electron in an orbital. The energy cost of pairing this electron (or extra electron repulsion) means that it is easier to remove than might otherwise have been expected resulting in group 16 being lower in IE than group 15 despite the increase in Z_eff and decrease in size.

Scientific Practices

Most Frequent Science Practices
Developing and Using Models Instruction presents an event, observation, or phenomenon for instructor/students to explain or make a prediction about. Instruction presents a representation or asks instructor/students to construct a representation. Instruction has instructor/students explain or make a prediction about the event, observation, or phenomenon. Instruction has instructor/students provide the reasoning that links the representation to their explanation or prediction.
Analyzing and Interpreting Data Instruction presents a scientific question, claim, or hypothesis to be investigated. Instruction provides a representation of data, such as a table, graph, or list of observations, used to answer the question or test the claim or hypothesis. Instruction provides an analysis of the data or asks instructor/students to analyze the data. Instruction has instructor/students interpret the results or assess the validity of the conclusions in the context of the scientific question, claim, or hypothesis.
Constructing Explanations and Engaging in Argument from Evidence Instruction presents an event, observation, or phenomenon. Instruction presents or asks instructor/students to make a claim based on the given event, observation, or phenomenon. Instruction has instructor/students provide scientific principles or evidence, such as data or observations, to support the claim. Instruction has instructor/students provide reasoning about why the scientific principles or evidence support the claim.

Multimedia Principles

Multimedia learning as knowledge construction: The goal of multimedia presentations is not only to present information but also to provide guidance for how to process the presented information – that is, for determining what to pay attention to, how to mentally organize it, and how to relate it to prior knowledge. We will categorize the videos along each of the following criteria (High and Low should be mutually exclusive.)

High	Low
Video almost exclusively involves meaningful and relevant images and verbal components AND images are explained for a novice learner Text on screen is minimal (ex. Only brief bullet points or keywords or definitions if text is used) Content is all relevant to the topic and learning (no music, unhelpful animations, graphics, etc.) Contains elements that meaningfully support student organizing content or identify key ideas (introductory organizer, section heading, summary, guiding questions/topic (for short, focused video only) Key Question: Could a novice learner clearly understand what they should take away from the video? Yes=high.	Large segments of video are presented just verbally and not pictorially (ex. just the instructor talking, or just written words) OR images presented are not relevant to learning or explained Contains full sentences of written text that are also narrated (e.g., several bullet points or sentences on one screen OR full sentences of text on many screens includes forced closed captioning) Contains extraneous content, music, graphics, animations, background changes, sounds, or just too much stuff on the screen at one time - anything that detracts attention from core content Does not contain any elements that meaningfully help learners organize content or identify key ideas (e.g., no introductory organizer, section headings, video segments, summary, guiding question/topic (for short focused videos only)

High

Low

Video almost exclusively involves meaningful
and relevant images and verbal components
AND images are explained for a novice
learner
Text on screen is minimal (ex. Only brief
bullet points or keywords or definitions if text
is used)
Content is all relevant to the topic and learning
(no music, unhelpful animations, graphics,
etc.)
Contains elements that meaningfully support
student organizing content or identify key
ideas (introductory organizer, section heading,
summary, guiding questions/topic (for short,
focused video only) Key Question: Could a
novice learner clearly understand what they
should take away from the video? Yes=high.

Large segments of video are presented just
verbally and not pictorially (ex. just the
instructor talking, or just written words) OR
images presented are not relevant to learning
or explained
Contains full sentences of written text that are
also narrated (e.g., several bullet points or
sentences on one screen OR full sentences of
text on many screens includes forced closed
captioning)
Contains extraneous content, music, graphics,
animations, background changes, sounds, or
just too much stuff on the screen at one time -
anything that detracts attention from core
content
Does not contain any elements that
meaningfully help learners organize content or
identify key ideas (e.g., no introductory
organizer, section headings, video segments,
summary, guiding question/topic (for short
focused videos only)

Misleading vs. Inaccuracies

Several minor spelling issues is misleading, not inaccurate

Example High Quality Videos

Examplar Videos

These are examples of videos that were found to provide good illustrations of some or many of the framework components for this concept. Develop a deep understanding of chemistry concepts requires multiple experiences with the material and these videos may provide one such experience.

Exemplar Video 1	Exemplar Video 2	Exemplar Video 3
Description This video compares first and second ionization energy using lithium as an example. It provides a Bohr diagram of lithium, gives the value for the first ionization energy, and then shows the second ionization energy after the first electron has been removed. The video explains the large difference between the two values using nuclear charge, effective nuclear charge, shielding, and distance from the nucleus.	Description This video begins with an overview and definition of ionization energy, then introduces second ionization energy. It discusses factors that influence ionization energy, including radius, nuclear charge, shielding, and distance. The video compares lithium and potassium using specific values, summarizes the trend down a group, examines the trend across a period, and then addresses successive ionization energies using data for the first through eleventh ionization energies.	Description This video begins with the second row of the periodic table and the ionization energy values for those elements. It identifies the general trend and then uses effective nuclear charge to compare lithium and beryllium. The video also explains deviations in the trend, including the difference between beryllium and boron using 2s and 2p orbital distance and repulsion, and the difference between nitrogen and oxygen using pairing energy.
Strengths This video addresses effective nuclear charge and multiple ionization energies while providing specific ionization energy data.	Strengths This video provides specific numeric ionization energy data, addresses multiple ionization energies, and explains effective nuclear charge.	Strengths This video addresses effective nuclear charge and provides exact ionization energy data.
Weaknesses The screen becomes a little messy by the end because of the circling and added information placed on top of the graphics.	Weaknesses This video ranks low for text because it consists mainly of an instructor talking over prepared notes and highlighting them.	Weaknesses This video ranks low in segmenting because there are no noticeable organizational tools for students.

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