8th Science Staar

Sodium and lithium have similar chemical properties. What characteristics of these elements explains why they are chemically similar?

• Their atoms both have one valence electron.

• Their atoms both have more neutrons than protons.

• Their atoms have the same number of energy levels.

• Their atoms contain equal numbers of protons and electrons.

The diagram shows a model of an atom. The model contains three different subatomic particles. Particle X and Y are inside the nucleus, and particle Z is outside the nucleus.

• Both particles X and Y have a positive charge. Particle Z has a negative charge.

• Both particles X and Y have a negative charge. Particle Z has a positive charge.

• Either particle X or particle Y has a positive charge. Particle Z has a negative charge.

• Either particle X or particle Y has a negative charge. Particle Z has a positive charge.

Tags

NGSS.MS-PS1-1

Students observe an unknown species during a field study. They observe that the organism is multicellular, is autotrophic, and can reproduce both sexually and asexually.

Which kingdom does this organism most likely belong to?

• Archaea

• Animalia

• Bacteria

• Plantae

Which element has chemical properties that are most similar to the chemical properties of sulfur, S?

• Silicon, Si

• Chlorine, Cl

• Selenium, Se

• Phosphorus, P

A student prepared diagrams to model atoms of two elements. Atoms of which two elements are represented by these models?

• Oxygen, O, and neon, Ne

• Fluorine, F, and neon, Ne

• Silicon, Si, and phosphorus, P

• Beryllium, Be, and boron, B

Tags

NGSS.MS-PS1-1

When a coin is tossed in the air, it travels upward, gradually slows down, momentarily reaches zero speed, then moves back downward with increasing speed. Which statement best explains this change in the coin’s motion?

• The force of gravity causes the coin to change its velocity.

• The coin’s inertia decreases on the way up and increases on the way down.

• The action-reaction force pair of gravity and the applied force cancel each other.

• The coin remains in its state of upward motion until the force of friction acts upon it.

Tags

NGSS.MS-PS2-2

NGSS.MS-PS2-4

Major surface currents of the ocean are shown in the diagram.

Ocean currents affect weather patterns by ---

• regulating when tides occur in coastal areas

• trapping heat at the equator to regulate the global climate

• distributing heat from the uneven absorption of solar energy

• increasing the rate of evaporation to transport water to areas experiencing droughts

Tags

NGSS.MS-ESS2-6

Students view two different cells under a microscope. They record their observations in the table shown.

Based on the organelles observed, the students determine that cell 2 is a plant cell because it has an organelle that ---

• allows water to enter and exit the cell

• contains genetic information

• stores water and nutrients

• produces its own food

Tags

NGSS.MS-LS1-2

The Hertzsprung-Russell diagram shown is divided into four sections.

Which section of the diagram includes the coolest, brightest stars?

• Section 1

• Section 2

• Section 3

• Section 4

Tags

NGSS.HS-ESS1-3

A skater pushes off a wall and skates backward for a few meters before stopping. Which statement best describes an action–reaction force pair in this situation?

• The wall pushes on the skater when the skater pushes on the wall.

• The wheels slow down, and the skater stops.

• The skater exerts a force on the wall, and the wheels exert a force on the floor and begin to turn.

• The friction of the floor decreases when the wheels roll on the floor.

Tags

NGSS.MS-PS2-1