Science TEKS

How many protons, neutrons, and electrons are present in an atom of hafnium, Hf, with a mass number of 178?

• 72 protons, 178 neutrons, 106 electrons

• 72 protons, 106 neutrons, 72 electrons

• 178 protons, 250 neutrons, 72 electrons

• 106 protons, 72 neutrons, 106 electrons

The table shows the chemical formulas for four substances. Which substances have the same number of carbon atoms?

• Substances 1 and 2

• Substances 2, 3, and 4

• Substances 2 and 3 only

• Substances 1 and 3

Tags

NGSS.MS-PS1-1

Tin, Sn, is a soft white metal. It has a low melting point compared with other metals. Tin is widely used as a coating for cans of food. Which statement accurately describes atoms of tin?

• Tin atoms have 50 protons.

• Tin atoms have five valence electrons.

• Tin atoms have 119 neutrons.

• Tin atoms have 68 electrons.

Tags

NGSS.MS-PS1-1

A balance and a graduated cylinder are used to determine the density of a mineral sample. The sample has a mass of 14.7g and a volume of 2.2cm³ .What is the density of the mineral sample?

• 0.15 g/cm³

• 32 g/cm³

• 13 g/cm³

• 6.7 g/cm³

A researcher wants to experiment with an element that reacts like phosphorus (P) but has a greater atomic mass. Which element should the researcher select for the experiment?

• Nitrogen (N)

• Sulfur (S)

• Arsenic (As)

• Silicon (Si)

When trying to identify an unknown element, a scientist determines what other elements the unknown element reacts with chemically. Which property of the unknown element determines the other elements it reacts with?

• The total number of neutrons in the unknown element

• The total number of particles in the nuckleus of the unknown element

• The number of protons in the nucleus of the unknown element

• The number of valence electrons in the unknown wlwment

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

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

• +25

• +30

• -25

• -30

The chemical equation shown below represents a reaction that produces fuel for certain cars. Which substance represented in this equation is classified as an element?

• CO

• H₂O

• CO₂

• H₂

Tags

NGSS.MS-PS1-1

An atom of a certain element has 36 protons, 36 electrons, and a mass number of 84. At room temperature this element is a very stable gas. How many neutrons are in this atom?

• 36

• 84

• 48

• 72

What is the atomic number of oxygen?

• 5

• Sandwich

• 8

• 17

Tags

NGSS.MS-PS1-1