TEKS 8.5B

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

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NGSS.MS-PS1-1

An atom of which element is represented by this model?

• Carbon (C)

• Neon (Ne)

• Sodium (Na)

• Boron (B)

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NGSS.MS-PS1-1

A student is studying calcium, a highly reactive element that humans need for strong bones. Which characteristic of calcium is most closely related to its chemical reactivity?

• The 20 protons in each atom of calcium

• The 2 valence electrons in each atom of calcium

• The atomic mass of calcium, which is 40.078 amu

• The density of calcium, which is 1.54 g/cm3

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NGSS.HS-PS1-1

NGSS.HS-PS1-2

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

An atom has 11 protons, 12 neutrons, and 11 electrons. What is the identity of the element?

• Sodium

• Titanium

• Vanadium

• Magnesium

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NGSS.MS-PS1-1

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

The element Barium (Ba) is made of particles with different atomic charges. Barium has how many neutrons located in it?

• 80 Neutrons

• 81 Neutrons

• 137 Neutrons

• 56 Neutrons

Which of the following properties of carbon distinguishes it from all other elements?

• Carbon has six protons in its nucleus

• Carbon forms compounds with oxygen

• Carbon is a gray solid at room temperature

• Carbon can be found in Earth’s crust

An element’s reactivity and other chemical properties are determined by the number of -

• isotopes it has.

• oxidation states.

• valence electrons.

• orbitals in an atom.

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NGSS.HS-PS1-1

NGSS.HS-PS1-2

Which of the following properties uniquely identifies every element?

• Number of valence electrons

• Charge of the atom

• Number of neutrons

• Number of protons