Q: How many atoms are present in $$2.50$$ moles of carbon?

$$1.51 \times 10$$^{24}$$ atoms

Question 1

Which of the following statements best describes the arrangement of electrons in an atom according to the energy level diagram shown in the first image?

Accepted Answer

Electrons fill the lowest available energy levels first, starting with $$n=1$$ closest to the nucleus.

Question 2

How many valence electrons does an atom of sulfur (S) have, based on the periodic table and electron arrangement chart?

Accepted Answer

$$6$$

Question 3

Which of the following elements will form a $$2+$$ cation by losing two valence electrons?

Accepted Answer

Magnesium (Mg)

Question 4

What is the correct formula for the ionic compound formed between magnesium and chlorine?

Accepted Answer

$$\mathrm{$$MgCl_2$$}$$

Question 5

Which of the following best explains why sodium forms a $$1+$$ ion and chlorine forms a $$1-$$ ion?

Accepted Answer

Sodium loses one electron to achieve a noble gas configuration, while chlorine gains one electron to achieve a noble gas configuration.

Question 6

Which of the following is a polyatomic ion?

Accepted Answer

$$\mathrm{SO_4$^{2-}}$$

Question 7

What is the correct name for the compound $$\mathrm{$$KNO_3$$}$$?

Accepted Answer

Potassium nitrate

Question 8

Which of the following molecules is nonpolar?

Accepted Answer

$$\mathrm{CO_2$}$$

Question 9

What is the molecular shape of methane ($$\mathrm{CH_4$}) $$according to VSEPR theory?

Accepted Answer

Tetrahedral

Question 10

Which of the following statements about electronegativity is correct?

Accepted Answer

Electronegativity increases across a period and decreases down a group.

Question 11

How many atoms are present in $$2.50$$ moles of carbon?

Accepted Answer

$$1.51 	imes 10$$^{24}$$ atoms

Question 12

What is the molar mass of $$\mathrm{H_2O}$$?

Accepted Answer

$$18.02 g/$$mol

Question 13

Which of the following compounds is named correctly?

Accepted Answer

$$\mathrm{N_2O}$$: dinitrogen monoxide

Question 14

Which of the following best describes the bonding in $$\mathrm{O_2$}$$?

Accepted Answer

A double covalent bond

Question 15

A molecule of ammonia ($$\mathrm{NH_3$}) $$has what molecular geometry?

Accepted Answer

Pyramidal

Question 16

Which of the following is the correct formula for dinitrogen trioxide?

Accepted Answer

$$\mathrm{N_2O_3}$$

Question 17

How many moles of $$\mathrm{CH_4$}$$ are present in $$32.10$$ grams of $$\mathrm{CH_4$}$$? (Molar mass $$= 16.05 g/$$mol)

Accepted Answer

$$2.00$$ moles

Question 18

Which of the following is a property of ionic compounds?

Accepted Answer

Electrically neutral overall

Question 19

What is the correct name for $$\mathrm{$$FeCl_3$$}$$?

Accepted Answer

Iron(III) chloride

Question 20

Which of the following best describes the difference between a cation and an anion?

Accepted Answer

A cation is positively charged and formed by losing electrons, while an anion is negatively charged and formed by gaining electrons.

Compounds and Chemical Bonding: Electron Arrangements, Ions, and Molecular Structure

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