AP Chemistry Review

How many neutrons does C-14 contain? (tap to enlarge the image)

• 6

• 7

• 14

• 8

Tags

NGSS.MS-PS1-1

If X is the symbol for an element, which of the following two symbols represent isotopes of the same element?   I. ⁷⁷₃₅X  II. ⁷⁷₃₃X  III. ⁸¹₃₇X  IV. ⁸¹₃₅ X

• I and II

• III and IV

• I and IV

• I and III

Four isotopes of lead include lead-204, lead-206, lead-207, and lead-208.  The average atomic mass of lead is 207.2.  Which isotope of lead is likely to be the most abundant.

• 204

• 206

• 207

• 208

An element has two naturally occurring isotopes. One is 10.013 amu and is 19.9% abundant. The other is 11.01 amu and is 80.1% abundant. What is the average atomic mass? What element is it?

• 9.012, Beryllium

• 12.011, Carbon

• 6.941, Lithium

• 10.812, Boron

• 12
• 7
• 8
• 14

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

• 2
• 8
• 3
• 13

Tags

NGSS.HS-PS1-1

Which element has the electron configuration 1s²2s²2p⁶3s²3p⁵?

• chlorine

• fluorine

• sulfur

• phosphorus

Tags

NGSS.HS-PS1-1

Which element is represented by this PES graph?

• argon

• potassium

• calcium

• scandium

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

Researchers from the planet Zorba have discovered an atom with the following electron structure (shown as a shell model). Sketch the photoelectron spectrum that the researchers analyzed to obtain this knowledge of atomic structure.

• 1s³2s¹2p⁶3s³

• 1s³2s¹2p⁴3s³

• 1s²2s²2p⁶3s²3p¹

• 1s²2s²2p⁶3s²

Answer explanation

Each level in this picture represents a sub shell of the atom. Carefully count the number of electrons for each sub shell.

Tags

NGSS.HS-PS1-1

The photoelectron spectra of the 1s electrons of two isoelectronic species, Ca²⁺ and Ar, are shown above. Which of the following correctly identifies the species associated with peak X and provides a valid justification?

• Ar, because it has completely filled energy levels.

• Ar, because its radius is smaller than the radius of Ca²⁺

• Ca²⁺, because its nuclear mass is greater than that of Ar

• Ca²⁺, because its nucleus has two more protons than the nucleus that Ar has

Answer explanation

Ca²⁺ has a greater nuclear charge than Ar, and so has a stronger attraction on the 1s electrons than Ar

Tags

NGSS.HS-PS1-1