Unit 2 Review

Most of the MASS Number of an atom is determined by # of _________?

• protons and electrons
• protons and neutrons
• neutrons and electrons
• electrons and quarks

Answer explanation

recall that protons and neutrons are called nucleons.

They are in the nucleus. Each is considered to have 1 u of mass if thinking about a single atom.

(that would scale up to be 1 gram each if we are thinking about moles instead of atoms)

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NGSS.MS-PS1-1

Which subatomic particle has a negative charge within the atom?

• proton
• electron
• neutron
• nucleus

Answer explanation

electron is negative, e^-

proton is positive, p⁺

neutron is neutral, n⁰

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How many protons does an atom of POTASSIUM have?

(Use Periodic Table)

• 19

• 15

• 39

• 31

Answer explanation

The element symbol for potassium is K.

K is atomic number 19 on the Periodic Table.

(bolded whole number)

# protons = atomic number

Trick answers were the atomic mass of potassium, 39, the atomic number of phosphorus... element symbol P... of 15, and phosphorus's atomic mass of 31.

Potassium, K, is one of those elements where the name and symbol don't line up well in English.

Tags

NGSS.MS-PS1-1

The atomic number of any atom is equal to _.

• the number of protons.

• the number of neutrons only
• the total number of protons and neutrons
• the number of protons neutrons and electrons

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NGSS.MS-PS1-1

How many electrons does this magnesium ion have?

• 24

• 12

• 10

• 14

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Carbon-13 differs from carbon-12 by:

• 1 extra neutron
• 1 less neutron
• 1 extra proton
• 1 extra electron

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the central region of an atom where its neutrons and protons are is its 

• nucleus 
• electron cloud
• core 
• center 

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24.1% of all the isotopes of a an element have a mass of 75.23 amu, 48.7% have a mass of 74.61 amu, and 27.2% have a mass of 75.20 amu.
What is the average mass of this element?

• 74.92 amu
• 24.97 amu
• 75.01 amu
• 74.51 amu

Which element is pictured?

• neon
• fluorine
• magnesium
• argon

Tags

NGSS.HS-PS1-1

Identify the Electron Configuration for Aluminum (Al)

• 1s² 2s² 2p⁶ 3s² 3p¹
• 1s² 2s² 2p⁶ 3s² 3p³
• 1s² 2s² 2p⁶ 3s² 4p¹

Tags

NGSS.HS-PS1-1