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

Tags

NGSS.MS-PS1-1

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

Tags

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

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.

• Student 1

• Student 2

• Student 3

• Student 4

Tags

NGSS.MS-PS1-1

List the steps of the scientific method

d

e

f

c

b

a

Communicate results

Conduct experiment

Ask a question

Form a hypothesis

Draw conclusions

Analyze results

Tags

NGSS.MS-LS1-5

Which letter represents amplitude? (a)  

• A

• B

• C

• D

• E

Tags

NGSS.MS-PS4-1

How do electrons of an element determine that element's reactivity?

• If the valence shell has missing electrons it is very reactive to attract or lose more electrons.

• If the valence shell has a full ring of electrons it is very reactive because it needs more.

• If the valence shell has a full shell of electrons it is very reactive because it is already full.

• If the valence shell has missing electrons it is not reactive because it is missing electrons.

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

What are valence electrons?

• The total number of electrons in an atom

• The number of electrons in the outermost shell

• The number of electrons in the second shell

• The number of protons in the outermost shell