Cde Science

A Student drew atomic models of four atomic models. Based on the drawings, which one is the least reactive?

• Chlorine, because it has three energy levels with seven electrons in the third level

• Gallium, because it has four energy levels with three electrons in the fourth level

• Neon, because it has two energy levels with eight electrons in the second level

• Tin, because it has five energy levels with four electrons in the fifth level

Tags

NGSS.MS-PS1-1

An atom consists of 12 protons, 12 electrons, and 12 neutrons. Which of the following can be used to identify the element?

• Neutrons

• Electrons

• Atomic number

• Atomic mass

A chemist is identifying the elements present in a sample of seawater. What characteristic of an element’s atoms always determines the element’s identity?

• The number of neutrons

• The number of protons

• The location of valence electrons

• The number of valence electrons

Four students were asked to name the parts of an atom that determine the atom’s identity and chemical properties. The students’ responses are shown in the table below.

• Student 1

• Student 2

• Student 3

• Student 4

Tags

NGSS.MS-PS1-1

Design an experiment to test the effect of sunlight on plant growth in different ecosystems.

• Plant seeds in identical pots under different light conditions and measure growth over a month.

• Plant seeds in the dark and observe for a day.

• Compare plant growth by reading a textbook.

• Ask others about their plant growth observations.

Tags

DOK Level 3: Strategic Thinking

How would you investigate the impact of pH levels on aquatic life in a freshwater biome?

• Read articles about freshwater biomes.

• Change the pH of a water sample and observe the behavior of aquatic organisms.

• Visit a freshwater biome once.

• Draw pictures of aquatic organisms.

Tags

DOK Level 3: Strategic Thinking

What reasoning would you use to explain why biodiversity is typically higher in a rainforest than in a desert?

• Rainforests have more sunlight.

• Deserts are cooler than rainforests.

• Rainforests have more varied resources and stable climates that support diverse species.

• Rainforests are larger in area than deserts.

Tags

DOK Level 3: Strategic Thinking

What is the primary function of chlorophyll in the ecosystems?

• To absorb water

• To produce carbon dioxide

• To absorb sunlight

• To release oxygen

Tags

DOK Level 1: Recall

Plan a project to analyze the effects of deforestation on local biomes.

• Write a poem about trees.

• Measure tree heights in a deforested area vs. a non-deforested area over a year.

• Watch a documentary on forests.

• Paint a picture of a forest.

Tags

DOK Level 3: Strategic Thinking

How do electrons of an element determine that element's reactivity?

• If the valence shell has missing electrons it is very reactive to attract or lose more electrons.

• If the valence shell has a full ring of electrons it is very reactive because it needs more.

• If the valence shell has a full shell of electrons it is very reactive because it is already full.

• If the valence shell has missing electrons it is not reactive because it is missing electrons.