{{asɛmtiNe Ɔkyerɛwfo}} | Nhomakorabea | Nneɛma a ɛma wotumi yɛ ade

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When you hear the word "trend," what do you think of?
I will grade these individually; it will show as wrong until I grade it

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Type one thing you notice about this picture.

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Add one thing you wonder about this photo

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Describe how the Matryoshka (Russian) Dolls are organized.

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Place the following objects from smallest to largest.

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If I say something is increasing, how would you order the items?

From smallest to largest

From largest to smallest

From earliest to latest

From latest to earliest

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If I say something is decreasing, how would you order the items?

From largest to smallest

From smallest to largest

From latest to earliest

From earliest to latest

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Match the following terms to the corresponding images size:

Draggable item		Corresponding Item
decreasing
constant
increasing

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Based on the trend in the graph, predict the size of object 7.

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Consider this graph.
In 1–2 sentences, explain what a trend is.

PERIOD

A period is a horizontal row that goes left to right across the periodic table.

An element’s period number tells you how many occupied energy levels (electron shells or rings) its atoms have.

ENERGY LEVELS

Energy levels are regions around the nucleus where electrons are found. In a Bohr model, they are shown as rings or shells.

The first energy level is closest to the nucleus.
Higher-energy levels are farther from the nucleus and contain electrons with higher energy.
As you move down the periodic table, atoms gain additional occupied energy levels.

Example: Carbon is in Period 2, so its electrons occupy two energy levels.

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What do the horizontal rows in the periodic table indicate?

The reactivity of the elements.

The number of electron rings in atoms.

The state of matter of each element.

The atomic number of elements.

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GROUP

A group is a vertical column that goes up and down the periodic table.

For main-group elements (ignore the transition metals—the yellow elements), elements in the same group usually have the same number of valence electrons.

VALENCE ELECTRONS

Valence electrons are the electrons in an atom’s outermost occupied energy level (shell or ring).

Atoms are most stable when their outer energy level is full. For most main-group elements, this means having 8 valence electrons. This is called the octet rule.

Because elements in the same group have the same number of valence electrons, they have similar chemical properties and reactivity.

Example: Group 1 elements have 1 valence electron and are highly reactive metals.

**Important exception: Helium has only 2 valence electrons, but its first energy level is full, so it is stable.

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BOHR MODEL

A Bohr model is a simplified picture of an atom. It shows the nucleus in the center and the electrons arranged in energy levels around it.

Notice the different names used for the rings and electrons:

The rings may be called shells or energy levels.
Electrons in the outermost occupied energy level are called valence electrons.
Electrons in the inner energy levels are called core electrons or inner electrons.

Valence electrons are especially important because they determine how an atom bonds and reacts with other atoms.

Note: An orbital is not another name for an energy level or ring. Orbitals are smaller regions within energy levels where electrons are most likely to be found.

Add these notes on the back of worksheet

Examples

Attraction between oppositley charged particles is goverened by Coulomb's Law. In this assignement you will explore the factors involved.

Learning Goals: Students will be able to

Determine what makes a force attractive or repulsive
Relate the electrostatic force magnitude to the charges and the distance between them

Explore the interactive below.

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How does this simulation model how charges interact?

In the interactive below, open the macro scale screen and explore the forces between two particles (atoms shaped like people).

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Using the pHet lab above, determine what makes a force attractive or repulsive. Describe your experiments and observations with some examples.

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How does the value of the electrostatic force vary with the value of the charges?

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How does the value of the electrostatic force vary with the distance between them?

Coulombic attraction is the force of attraction between oppositely charged particles.

In an atom, the positively charged protons in the nucleus attract the negatively charged electrons.

Coulombic attraction becomes:

Stronger when there are more protons pulling on the electrons.
Weaker when the electrons are farther from the nucleus or shielded by more inner electrons.

This attraction helps explain periodic trends such as atomic radius, ionization energy, and electronegativity.

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What does Coulombic attraction describe?

Attraction between oppositely charged particles.

Repulsion of electrons in atoms.

Force between similar charged particles.

Attraction of nuclei in atoms.

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BOHR MODEL

A Bohr model is a simplified picture of an atom. It shows the nucleus in the center with electrons arranged in energy levels around it.

Know the Vocabulary

Many names, same thing

Energy levels = shells = rings
Valence electrons = electrons in the outermost occupied energy level
Core (inner) electrons = electrons in the inner energy levels

⭐ Why are valence electrons important? Valence electrons help determine how an element bonds and reacts with other elements.

⚠️ Energy Level ≠ Orbital

An orbital is not another name for an energy level or ring. Orbitals are smaller regions within an energy level where electrons are most likely to be found.

For now, think: Energy level → contains orbitals → orbitals contain electrons

Intro to Periodic Trends (short)