8.5a 8.5b 8.5c

• 2
• 6
• 10
• 16

Tags

NGSS.MS-PS1-1

An atom of which element is represented by this model?

• Carbon (C)

• Neon (Ne)

• Sodium (Na)

• Boron (B)

Tags

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

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

How many valence electrons does the atom of Carbon-14, shown above have?

• 14

• 10

• 6

• 4

Tags

NGSS.MS-PS1-1

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.

Tags

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

Q1. How many apples are there?

• 2

• 8

• 3

• 13

Valence electrons are electrons in the shell

• furthest from the nucleus

• closest to the nucleus

• having the lowest energy level

• that has the fastest electrons

All atoms are most stable with (or would "prefer") how many electrons in their valence shell?

• 1

• 2

• 8

• 18