Category 1 Science STAAR Review

Which statement correctly describes the location and charge of the electrons in an atom?

• The electrons are inside the nucleus and have no charge.

• The electrons are outside the nucleus and have no charge.

• The electrons are inside the nucleus and have a negative charge.

• The electrons are outside the nucleus and have a negative charge.

Which of the following best describes an electron?

• It has no charge and about the same mass as a proton.

• It has a negative charge and much less mass than a proton.

• It has a positive charge and much more mass than a neutron.

• It has a negative charge and about the same mass as a neutron.

Tags

NGSS.MS-PS2-3

An atom has 25 protons, 30 neutrons, and 25 electrons. What is the charge of the atom's nucleus?

• +25

• +30

• -25

• -30

A student drew atomic models of four element.
Based on these drawings, which element is the least reactive?

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

• Chlorine, because is 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

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

Tags

NGSS.MS-PS1-1

What does solubility refer to?

• The ability of a substance to dissolve in another substance.

• The temperature at which a liquid turns into a solid.

• The ability of a substance to react with oxygen.

• The temperature at which a solid turns into a liquid.

A chemist made the table below to record some atomic properties of four elements.
Based on the information in the table, which conclusion about the chemical reactivity of these elements is valid?

• Boron is the most reactive because it has the most protons.

• Fluorine is the most reactive because it has 7 electrons in the outer shell.

• Silicon is the most reactive because it has an equal number of protons and neutrons.

• Gallium is the most reactive because it has many more neutrons than protons.

Tags

NGSS.MS-PS1-1

NGSS.MS-PS1-2

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.

Which student's responses are correct?

• Student 1

• Student 2

• Student 3

• Student 4

Tags

NGSS.MS-PS1-1

The atoms of a certain element contain 11 protons and 1 valence electron. Which statement correctly identifies the element and describes its chemical reactivity?

• The element is sodium, and it is highly reactive.

• The element is fluorine, and it is not very reactive.

• The element is sodium, and it is not very reactive.

• The element if fluorine, and it is highly reactive.

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

• The number of protons

• The number of neutrons

• The location of the valence electrons

• The number of valence electrons

The table below lists three characteristics of an atom of an element.

An atom of which element is described by the data in the table?

• Radon (Rn)

• Cadmium (Cd)

• Rubidium (Rb)

• Astatine (At)

Tags

NGSS.MS-PS1-1