Pre-Test

How many atoms are there in 1.25 moles of Zn?

•  $6.53\ \times10^{23}$  

•  $7.59\ \times10^{23}$  

•  $8.53\ \times10^{23}$  

•  $9.53\ \times10^{23}$  

Positively charged ions are obtained when

an atom ________________.

• gain electron

• lose proton

• Lose electron

• gain neutron

The molecular mass of benzene C₆H₆.

• 72

• 78

• 25

• 68

Find the number of neutrons in an atom M, whose atomic number is 14 and mass number is 27 :

• 14

• 27

• 13

• 41

The electronic configuration of an atom is 1s², 2s² _,2p⁶, 3s¹. It is denoted by the following symbol?

• Ne

• Na

• Cl

• Mg

What principle states that the lower energy levels must be filled with electrons first before building up the higher energy levels?

• Aufbau Principle
• Hund's Rule
• Pauli Exclusion Principle
• Uncertainty Principle

In a mass spectrometer, chlorine may exist as Cl²⁺ ions. Which of the following represents the electronic configuration of the Cl²⁺ ion? (Proton number of chlorine = 17)

• 1s²2s²2p⁶3s²3p³

• 1s²2s²2p⁶3s²3p⁶

• 1s²2s²2p⁶3s²3p⁵

• 1s²2s²2p⁶3s²3p²

What is the definition of the term isoelectronic?

• Isoelectronic is the force that pushes all the electrons of an atom away from the nucleus.

• Isoelectronic atoms or ions have the same number of electrons and therefore they have the same electronic configurations.

• Isoelectronic atoms or ions have different number of electrons and therefore they have different electronic configurations.

• Isoelectronic is the force that pulls all the electrons of an atom to the nucleus.

Most elements on the periodic table are classified as ____________.

• Gases

• Metalloids

• Metals

• Nonmetals

How many neutrons does Chlorine have?

• 17

• 36

• 35

• 18