Topic 1a and b (Chemistry)

Question 1

What are the three main subatomic particles and where are they located within an atom?

Answer 1

The three main subatomic particles are protons, neutrons, and electrons. Protons and neutrons are located in the nucleus of an atom, while electrons are found in electron shells surrounding the nucleus.

Question 2

Why are atoms electrically neutral despite containing charged particles?

Answer 2

Atoms are electrically neutral because there are equal numbers of positive protons and negative electrons. The charges cancel each other out.

Question 3

How do you determine the identity of an element based on its atomic structure?

Answer 3

The identity of an element is determined by the number of protons in its nucleus, known as the atomic number. Each element has a unique atomic number, which distinguishes it from other elements.

Question 4

Define atomic number and explain its significance in identifying elements.

Answer 4

The atomic number is the number of protons in the nucleus of an atom. It is significant because it determines the identity of the element. Elements are arranged in the periodic table based on their atomic numbers.

Question 5

What is the difference between an atom and an element?

Answer 5

An atom is the smallest particle of a particular element, consisting of a nucleus containing protons and neutrons, surrounded by electrons. An element, on the other hand, is a substance made of only one type of atom.

Question 6

How does the atomic mass differ from the atomic number?

Answer 6

The atomic number represents the number of protons in the nucleus of an atom, while the atomic mass represents the total number of protons and neutrons. Atomic mass is measured in atomic mass units (amu).

Question 7

Why are electrons crucial in determining the chemical behavior of an element?

Answer 7

Electrons are crucial because they participate in chemical reactions. The arrangement of electrons in the electron shells determines an atom’s chemical properties, such as its reactivity and ability to form bonds with other atoms.

Question 8

Define compound and explain how it differs from an element.

Answer 8

A compound is a substance made up of two or more different types of atoms chemically bonded together. Unlike an element, which consists of only one type of atom, a compound contains atoms of different elements bonded in fixed ratios.

Question 9

How does the arrangement of electrons in an atom determine its chemical properties?

Answer 9

The arrangement of electrons in the electron shells determines an atom’s chemical properties by influencing its reactivity and ability to form bonds. The number of electrons in the outermost shell (valence electrons) is particularly important in determining how an atom will interact with other atoms

Question 10

What are the relative masses of protons, neutrons, and electrons?

Answer 10

Protons and neutrons have a relative mass of 1, while electrons have a relative mass of approximately 0 (considered negligible).

Question 11

What are the relative charges of protons, neutrons, and electrons?

Answer 11

Protons have a relative charge of +1, neutrons have a relative charge of 0, and electrons have a relative charge of -1.

Question 12

What is the relative mass of a proton, and what is its charge?

Answer 12

A proton has a relative mass of 1 and a charge of +1.

Question 13

What is the relative mass of a neutron, and what is its charge?

Answer 13

A neutron has a relative mass of 1 and a charge of 0.

Question 14

What is the relative mass of an electron, and what is its charge?

Answer 14

An electron has a relative mass close to 0 and a charge of -1.

Question 15

What is electron configuration?

Answer 15

Electron configuration is the distribution of electrons in an atom as they are arranged in electron shells around the nucleus.

Question 16

How many electrons can the first shell of an atom hold, and how are they arranged?

Answer 16

The first shell can hold up to 2 electrons, which are arranged with one electron in each of the two available subshells, often referred to as “UP” and “DOWN.”

Question 17

How many electrons can the second shell of an atom hold, and how are they arranged?

Answer 17

The second shell can hold up to 8 electrons, arranged with two electrons in the first subshell (“UP” and “DOWN”) and six electrons in the second subshell (arranged as “LEFT,” “RIGHT,” “LEFT,” “RIGHT,” “LEFT,” “RIGHT”).

Question 18

How many electrons can the third shell of an atom hold, and how are they arranged?

Answer 18

The third shell can hold up to 8 electrons, similarly arranged to the second shell, with two electrons in the first subshell (“UP” and “DOWN”) and six electrons in the second subshell (arranged as “LEFT,” “RIGHT,” “LEFT,” “RIGHT,” “LEFT,” “RIGHT”).

Question 19

How many electrons can the fourth shell of an atom hold, and how are they arranged?

Answer 19

The fourth shell can hold up to 2 electrons, with one electron in each of the two available subshells (“UP” and “DOWN”).

Question 20

What kind of diagrams are often used to represent electron configurations?

Answer 20

Diagrams depicting electron configurations often use circles or shells around the nucleus, with arrows or dots representing electrons and indicating their distribution among the shells.

Question 21

How can the periodic table help determine the number of electron shells and outer shell electrons of an atom?

Answer 21

The period (row) on the periodic table corresponds to the number of electron shells, while the group number (column) indicates the number of outer shell electrons.

Question 22

What is the “shorthand” method for writing out electronic configurations?

Answer 22

The shorthand method represents the electron configuration using numbers separated by periods, where each number represents the number of electrons in each shell. For example, “2.8.8.2” indicates an atom with 20 electrons, with 2 electrons in the first shell, 8 in the second and third shells each, and 2 in the fourth shell.

Question 23

How do you determine the number of neutrons in an atom?

Answer 23

The number of neutrons can be calculated by subtracting the atomic number (number of protons) from the atomic mass. Neutrons = Atomic Mass - Atomic Number.

Question 24

What is the relationship between the number of electron shells and the period of an atom on the periodic table?

Answer 24

The period (row) on the periodic table corresponds to the number of electron shells in an atom. Each period represents one additional shell compared to the previous period.

Question 25

How does the group number of an element relate to its outer shell electrons?

Answer 25

The group number (column) on the periodic table indicates the number of outer shell electrons in an atom. Elements within the same group have the same number of outer shell electrons.

Question 26

How can the periodic table help determine the number of electron shells and outer shell electrons of an atom?

Answer 26

The period (row) on the periodic table corresponds to the number of electron shells, while the group number (column) indicates the number of outer shell electrons.

Question 27

What is an isotope?

Answer 27

Isotopes are atoms of an element with the same number of protons but different numbers of neutrons.

Question 28

Give an example of isotopes of hydrogen and their respective numbers of protons, neutrons, and electrons.

Answer 28

Hydrogen has three isotopes: Hydrogen-1 (1 proton, 0 neutrons, 1 electron), Hydrogen-2 or Deuterium (1 proton, 1 neutron, 1 electron), and Hydrogen-3 or Tritium (1 proton, 2 neutrons, 1 electron).

Question 29

Do isotopes of an element have different chemical properties?

Answer 29

No, all isotopes of an element have the same chemical properties because they have the same number of electrons, which determine an element’s chemical behavior.

Question 30

What is the relative atomic mass (Ar) of an element, and how is it calculated?

Answer 30

The relative atomic mass (Ar) of an element is the weighted average of the relative atomic masses of its isotopes, taking into account their abundances. It is calculated using the formula: Ar = (mass1 * %abundance1 + mass2 * %abundance2 + …) / 100.

Question 31

How is the relative atomic mass (Ar) of an element determined using isotopic abundances?

Answer 31

The Ar of an element is calculated by multiplying the mass number of each isotope by its abundance (expressed as a percentage), summing these values, and dividing by 100. For example, for Chlorine, if 75% is ^35Cl and 25% is ^37Cl, the Ar would be calculated as: (7535 + 2537) / 100 = 35.5.

Question 32

What does the relative atomic mass (Ar) represent for an element?

Answer 32

The relative atomic mass (Ar) represents the average mass of the isotopes of an element, weighted by their relative abundances, compared to the mass of a carbon-12 atom (which has a defined atomic mass of 12).

Question 33

What are the key points of Dalton’s atomic model?

Answer 33

Dalton’s atomic model proposed that all matter is made up of tiny particles called atoms, which are indivisible and identical within an element. Atoms cannot be created or destroyed.

Question 34

What did JJ Thomson’s plum pudding model propose?

Answer 34

JJ Thomson’s plum pudding model suggested that atoms are spheres of positive charge with negatively charged electrons embedded within them.

Question 35

What were the key findings of Rutherford’s gold foil experiment, and what conclusions did he draw from them?

Answer 35

In Rutherford’s experiment, most alpha particles passed straight through the gold foil, but some were deflected at large angles, and a few were reflected back. From these results, Rutherford concluded that most of an atom is empty space, there is a dense positive nucleus at the center of the atom, and electrons orbit the nucleus.

Question 36

What did Bohr observe about the light emitted by heated atoms, and how did he interpret it?

Answer 36

Bohr observed that the light emitted by heated atoms always had specific amounts of energy. He concluded that electrons orbit the nucleus in fixed energy levels, and each energy level corresponds to a specific amount of energy. This led to the development of the Bohr model of the atom.

Question 37

How did Mendeleev originally organize the 60 known elements in his periodic table?

Answer 37

Mendeleev arranged the elements in order of increasing atomic mass, grouping them based on similarities in chemical properties. He also classified them into metals and non-metals.

Question 38

Why did Mendeleev’s original periodic table fail to accurately predict the properties of certain elements like iodine and tellurium?

Answer 38

Mendeleev’s periodic table did not account for isotopes, leading to inaccuracies in predicting the properties of elements with similar atomic masses. For example, iodine and tellurium had similar properties, but their atomic masses differed, causing them to be misplaced.

Question 39

What modifications did Mendeleev make to his periodic table to accommodate elements like iodine and tellurium?

Answer 39

Mendeleev swapped the positions of iodine and tellurium to align iodine’s properties with those of the elements in Group 7. He also left gaps in his table for undiscovered elements and predicted their properties, as in the case of germanium, which he named Ekasilicon.

Question 40

How does the modern periodic table differ from Mendeleev’s original version?

Answer 40

The modern periodic table has 118 elements arranged in order of increasing atomic number rather than atomic mass. It no longer contains gaps, as all known elements have been discovered and placed accordingly.

Question 41

What are periods and groups in the modern periodic table?

Answer 41

Periods are the horizontal rows in the periodic table, with the period number indicating the number of electron shells in an atom. Groups are the vertical columns, where elements within the same group share similar chemical properties, with the group number corresponding to the number of electrons in the outer shell.

Question 42

What are transition metals, and where are they located on the periodic table?

Answer 42

Transition metals are located in the middle section of the periodic table. They are characterized by their partially filled d orbitals and exhibit a wide range of oxidation states and metallic properties.

Question 43

How are transition metals typically represented in chemical formulas, and what charge do they usually carry?

Answer 43

Transition metals are typically represented with a Roman numeral indicating their charge, such as Lead(II) oxide for Pb^2+ ion or Iron(III) sulfate for Fe^3+ ion. Transition metals usually carry a 2+ charge, except for exceptions like silver, which carries a 1+ charge.

Question 44

What is the significance of the Roman numeral in transition metal compounds?

Answer 44

The Roman numeral in transition metal compounds indicates the charge of the metal ion. It helps specify the oxidation state of the metal, as transition metals can have multiple oxidation states.

Question 45

What are the typical charges for Group 1, Group 2, and Group 3 elements when they form ions?

Answer 45

Group 1 elements typically form ions with a 1+ charge, Group 2 elements form ions with a 2+ charge, and Group 3 elements form ions with a 3+ charge.

Question 46

How do Group 5 and Group 6 elements usually form ions?

Answer 46

Group 5 elements typically form ions with a 3- charge, while Group 6 elements form ions with a 2- charge.

Question 47

What is the general trend for metals and non-metals regarding electron gain or loss?

Answer 47

Metals tend to lose electrons to become positively charged ions or cations, while non-metals tend to gain electrons to become negatively charged ions or anions.

Question 48

Define ion, cation, and anion.

Answer 48

An ion is an atom or group of atoms with a positive or negative charge. A cation is a positively charged ion, typically formed by metals losing electrons. An anion is a negatively charged ion, usually formed by non-metals gaining electrons.

Question 49

What is the chemical formula for nitrate, and what is its charge?

Answer 49

The chemical formula for nitrate is NO3^1-, and it carries a charge of 1-.

Question 50

What is the chemical formula for sulfate, and what is its charge?

Answer 50

The chemical formula for sulfate is SO4^2-, and it carries a charge of 2-.

Question 51

What is the chemical formula for carbonate, and what is its charge?

Answer 51

The chemical formula for carbonate is CO3^2-, and it carries a charge of 2-.

Question 52

What is the chemical formula for hydroxide, and what is its charge?

Answer 52

The chemical formula for hydroxide is OH^1-, and it carries a charge of 1-.

Question 53

What is the chemical formula for ammonium, and what is its charge?

Answer 53

The chemical formula for ammonium is NH4^+, and it carries a charge of 1+.

Question 54

Define the term “key formula” and provide an example.

Answer 54

A key formula represents a compound or ion commonly encountered in chemical reactions. An example is hydroxide (OH^1-), which is often involved in acid-base reactions and in the naming of certain compounds.

Question 55

What is the chemical formula for magnesium ion, and what is its charge?

Answer 55

The chemical formula for magnesium ion is Mg^2+, and it carries a charge of 2+.

Question 56

What is the chemical formula for sulfide ion, and what is its charge?

Answer 56

The chemical formula for sulfide ion is S^2-, and it carries a charge of 2-.

Question 57

What is the formula for the compound formed when magnesium ion and sulfide ion combine?

Answer 57

When the charges of magnesium ion and sulfide ion cancel out, the compound formed is MgS.

Question 58

What is the chemical formula for aluminum ion, and what is its charge?

Answer 58

The chemical formula for aluminum ion is Al^3+, and it carries a charge of 3+.

Question 59

What is the chemical formula for chloride ion, and what is its charge?

Answer 59

The chemical formula for chloride ion is Cl^1-, and it carries a charge of 1-.

Question 60

How is the compound formed when aluminum ion and chloride ion combine correctly written?

Answer 60

The correct formula for the compound formed by aluminum ion and chloride ion is AlCl3.

Question 61

What is the chemical formula for nitrate ion, and what is its charge?

Answer 61

The chemical formula for nitrate ion is NO3^1-, and it carries a charge of 1-.

Question 62

What is the chemical formula for calcium ion, and what is its charge?

Answer 62

The chemical formula for calcium ion is Ca^2+, and it carries a charge of 2+.

Question 63

How are compounds named according to the double-barreled naming convention?

Answer 63

Compounds have a double-barreled name where the first part identifies one of the elements in the compound and the second part identifies another element.

Question 64

What does it indicate if the second part of the compound’s name ends in “IDE”?

Answer 64

If the second part ends in “IDE,” it indicates that there are only two elements in the compound.

Question 65

What does it indicate if the second part of the compound’s name ends in “ATE”?

Answer 65

If the second part ends in “ATE,” it indicates that there are the two elements already mentioned, and oxygen is also present in the compound.