Chemistry Exam: Pure Substances & Atomic Structure

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Questions and Answers

How many neutrons are present in an atom of fluorine-18?

11 (correct)

What is the formula for the monoatomic species with 23 protons, 21 electrons, and 30 neutrons?

V23+ (correct)

V1+

V2-

V1-

How many moles of hydrogen atoms are in 1.00 g of NH3BH3?

0.1

0.2 (correct)

0.03

0.5

What is the mass in grams of 1 atomic mass unit (amu) when using three significant figures?

1.66E-22 Signup and view all the answers

Which ions are present in Na2HPO4(s)?

Na+, HPO4^2- Signup and view all the answers

What should a student do if time is called during the examination?

Put the pencil down and remain seated Signup and view all the answers

What is the total number of pages included in this exam?

6 pages Signup and view all the answers

Which of the following substances is classified as a metal?

Bi Signup and view all the answers

When are students allowed to begin the examination?

After everyone has an exam Signup and view all the answers

What is the correct approach for noting down answers?

Only in the designated spaces provided Signup and view all the answers

Which of the following should not be done after the exam is collected?

Discuss exam questions Signup and view all the answers

What is a critical instruction related to significant figures?

Pay attention to the number of significant figures in your answer Signup and view all the answers

Which of the following substances is a covalent substance?

Graphene Signup and view all the answers

What is the systematic name for barium peroxide?

Barium peroxide Signup and view all the answers

What is the chemical formula for sodium hypochlorite?

NaClO Signup and view all the answers

What is the designation for the atomic orbital with quantum numbers n = 3, l = 0?

3s Signup and view all the answers

What is the maximum wavelength in nm that can ionize an atom with an ionization energy of 1402 kJ/mol?

894.5 nm Signup and view all the answers

What is the designation for the atomic orbital with quantum numbers n = 2, l = 1?

2p Signup and view all the answers

How many unpaired electrons are present in chromium (Cr) in its ground state configuration?

4 Signup and view all the answers

Which of the following atomic orbitals corresponds to two nodal planes, x = 0 and y = 0?

3d Signup and view all the answers

Which statement correctly describes the nature of the Ge2+ ion's ground-state electron configuration?

Has lost 2 electrons from the 4s sublevel Signup and view all the answers

Arrange these elements by their increasing atomic radius: Al, Ne, Ca.

Ne, Al, Ca Signup and view all the answers

Which species has the smallest ionic radius among I-, Br-, and Rb+?

Rb+ Signup and view all the answers

What is the correct order for electron affinity from most negative to least negative for Ne, H, and F?

F, H, Ne Signup and view all the answers

Rank the following from lowest to highest ionization energy: Li, N, Si.

Li, Si, N Signup and view all the answers

What is the empirical formula for Alizarin, given its mass percentages of C, H, and O?

C15H10O5 Signup and view all the answers

Determine which is unlikely to occur based on the properties of typical isotopes.

All isotopes of lead are stable. Signup and view all the answers

In the formula for energy emitted or absorbed by hydrogen atoms, what does the variable $n_{initial}$ represent?

Initial energy level Signup and view all the answers

Which of the following correctly matches the speed of light with its constant?

3.00 x 10^8 m/s Signup and view all the answers

What is the value of the Planck constant?

6.626 x 10^{-34} J·s Signup and view all the answers

Which of the following describes the average atomic mass calculation?

Weighted average of isotopic masses. Signup and view all the answers

What is the significance of Avogadro's number in chemistry?

It represents the number of particles in one mole. Signup and view all the answers

Which of the following elements would generally have a larger atomic radius?

An alkaline earth metal Signup and view all the answers

Which factor primarily influences the trends in ionization energy across a period?

Increasing nuclear charge Signup and view all the answers

Which of the following statements about electron transitions in hydrogen is accurate?

Energy can be emitted or absorbed. Signup and view all the answers

Study Notes

Exam Instructions

The exam contains 6 pages with 14 questions.
The Periodic Table of the Elements can be detached.
Use blank pages as scratch paper.
Put answers only in the space provided.
No unauthorized assistance is permitted.

Question 1: Classifying Pure Substances

Classify each of the following substances as a compound, covalent substance, metal, or non-metal: BeF2, Bi, SiO2, O3, He, graphene.

Question 2: Atomic Particles

a) Determine the number of protons, electrons, and neutrons in one atom of fluorine-18.
b) Given the number of protons, electrons, and neutrons, determine the formula of the monoatomic species.

Question 3: Moles and Avogadro's Number

Calculate the number of moles of hydrogen atoms in 1.00 g of NH3BH3 (molecular mass 30.87 amu).

Question 4: Mass of Atomic Mass Unit

Calculate the mass in grams of 1 atomic mass unit (amu) using the definition of the mole, the atomic mass unit, and physical constants provided on page 5.

Question 5: Identifying an Element from Atom Count

Identify the element in a 10.0 g sample containing 4.39 × 10^22 atoms.

Question 6: Ions in Substances

a) List the formulas of ions present in Na2HPO4(s).
b) List the major monoatomic cations derived from lead.
c) List the ions present in PI3(s).
d) List the ions present in Ti2O3(s).
e) List the major monoatomic anions derived from sulfur.

Question 7: Naming and Formula Writing

Provide the systematic name or chemical formula for each of the following substances:
- a) barium peroxide
- b) NaClO
- c) CuF2
- d) GeCl4
- e) aluminum hydrogen sulfate

Question 8: Ionization Energy and Wavelength

Calculate the maximum wavelength in nm of the electromagnetic wave that can ionize an atom with a first ionization energy of 1402 kJ/mol.

Question 9: Atomic Orbital Designations

Provide a designation (e.g., 4dxy) for the atomic orbitals with the given set of quantum numbers:
- a) n = 3, l = 0, with no nodal planes
- b) n = 2, l = 1, with a nodal plane x = 0
- c) n = 2, l = 2, with two nodal planes, x = 0 and y = 0

Question 10: Atomic Orbital Drawings

Provide a designation (e.g., 5p) for each of the atomic orbital drawings:
- a) Cross-section drawing of an atomic orbital
- b) Cross-section drawing of an atomic orbital

Question 11: Orbital Diagram of Ge2+

Provide the full orbital diagram for the Ge2+ ion in its ground state.

Question 12: Unpaired Electrons and Valence Electrons

a) Indicate the number of unpaired electrons in the following species in their ground state configuration:
- i) Ca, [Ar]4s2
- ii) Cr2+, [Ar]3d4
- iii) S, [Ne]3s23p4
b) Indicate the number of valence electrons in the following species: -i) Al -ii) Pd -iii) Xe

Question 13: Periodic Trends

Arrange the following species in order of increasing:
- a) Atomic radius: Al, Ne, Ca
- b) Ionic radius: I-, Br-, Rb+
- c) Electron affinity: Ne, H, F
- d) Ionization energy: Li, N, Si

Question 14: Empirical Formula of Alizarin

Determine the empirical formula of alizarin, a natural pigment containing 70.00% C, 3.36% H, and 26.64% O by mass.

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Description

This quiz covers key concepts in chemistry related to classifying pure substances, understanding atomic particles, and applying Avogadro's number. Test your knowledge on compounds, atomic mass, and calculations involving moles. Enjoy the challenge of these structured questions!