1.
What are isotopes?
Correct Answer
D. D) They have different number of neutrons but same number of protons.
Explanation
Alternatively, they have the same atomic number but different mass number.
2.
If a principal quantum
shell has the number n=2, what is the maximum number of electron it can have?
Correct Answer
D. 8
Explanation
n=2 is the second principal quantum shell. It is made up of an s orbital and p orbital which can store 2 and 6 electrons respectively. 2+6=8
3.
Which electronic configuration represents Chromium?
Correct Answer
C. C) 1s2 2s2 2p6 3s2 3p5 4s1
Explanation
A half filled d sub shell has extra stability.
4.
Given that Copper exists as copper 63 and copper 65 and their relative atomic mass is 63.6, find the relative abundance of each isotope.
Correct Answer
B. Cu 63 - 30 Cu 65 - 70
Explanation
let x = relative abundance of cu 63
63(x/100) + 65(1-x/100) = 63.6
x=70
Relative abundance of Cu 65 = 100-70
=30
5.
Particles, ions or atoms that have the same number of ... are isoelectronic?
Correct Answer
C. Electrons
Explanation
Particles, ions, or atoms that have the same number of electrons are isoelectronic. Isoelectronic species have the same electronic configuration, meaning they have the same number of electrons and therefore similar chemical properties. The number of protons and neutrons in an atom does not determine whether they are isoelectronic, as it is the number of electrons that primarily determines the element's behavior in chemical reactions.
6.
Which electronic
configuration is stable?
Correct Answer
A. A) 1s2 2s2 2p6
Explanation
A stable electronic configuration has a completely filled outermost principal quantum shell.
7.
Aufbau’s Principle states
that:
Correct Answer
A. A) Electrons in their ground state will occupy orbitals in order of their energy level; the lowest energy levels are always filled first.
Explanation
Aufbau's Principle is a fundamental principle in chemistry that describes the order in which electrons fill the orbitals of an atom. According to this principle, electrons in their ground state will occupy orbitals in order of their energy level, with the lowest energy levels being filled first. This means that electrons will fill the orbitals starting from the lowest energy level and moving up to higher energy levels. This principle helps to explain the organization of the periodic table and the electron configuration of atoms.
8.
Since isotopes have the same number of electrons, they then have the same...?
Correct Answer
A. Chemical properties
Explanation
Isotopes have the same number of electrons, which means they have the same electron configuration. This electron configuration determines the chemical properties of an element. Therefore, isotopes have the same chemical properties. The other options, melting point, boiling point, and density, are not solely determined by the number of electrons and can vary between isotopes.
9.
Element P has the electronic configuration 2.8.6.Element Q has the electronic configuration 2.8.8.2.Which statement about the compound PQ is probably correct?
Correct Answer
B. It will conduct electricity when molten.
Explanation
An ionic compound is formed.
10.
Xenon is in group 0. Which statement about xenon is true?
Correct Answer
D. Xenon is unreactive
Explanation
All noble gases are unreactive.
11.
In fleming's left hand rule, if the first finger is pointing at the field and the second finger is pointing at the current, then the thumb is at...?
Correct Answer
D. Direction of resultant force
Explanation
According to Fleming's left-hand rule, if the first finger represents the direction of the magnetic field and the second finger represents the direction of the current, then the thumb represents the direction of the resultant force. This means that the correct answer is "Direction of resultant force." The rule is commonly used to determine the direction of the force experienced by a current-carrying conductor in a magnetic field.
12.
What is the shape of the
p-orbital?
Correct Answer
A. Dumb-bell shape
Explanation
The p-orbital is shaped like a dumbbell, with two lobes on either side of the nucleus. This shape is a result of the wave-like nature of electrons and their probability distribution within the orbital. The dumbbell shape allows for the electron to move in different directions and orientations around the nucleus.
13.
The first period consists of two elements. How many elements does the second period consist of?
Correct Answer
B. 8
Explanation
In the periodic table, groups are the columns while periods are the rows.
14.
Which of the following are the properties of graphite?
Correct Answer
C. Soft, high melting point
Explanation
Graphite is a form of carbon that has a layered structure, with weak bonds between the layers. This structure gives graphite its soft and slippery texture, making it suitable for use as a lubricant. However, graphite also has a high melting point, which means it requires a significant amount of heat to change from a solid to a liquid state. This property makes graphite useful in high-temperature applications, such as in the production of crucibles and refractory materials. Therefore, the correct answer is "Soft, high melting point."
15.
Potassium and Francium are both in group I of the periodic table. Which one of the following statements is correct?
Correct Answer
C. Francium has a lower melting point than potassium.
Explanation
Francium has a lower melting point than potassium because as you move down Group I of the periodic table, the melting points of the elements decrease. This is due to the increase in atomic size and the weakening of metallic bonds. Francium, being below potassium in the group, has a larger atomic size and weaker metallic bonds, resulting in a lower melting point compared to potassium.
16.
Which combination is correct for diamond?
Correct Answer
A. Covalent bond, 4 atoms joined to each carbon atom
Explanation
Diamond is a form of carbon in which each carbon atom is covalently bonded to four other carbon atoms. This results in a three-dimensional network structure, giving diamond its hardness and unique properties. The covalent bonds are strong and stable, making diamond one of the hardest substances known. Therefore, the correct combination for diamond is "covalent bond, 4 atoms joined to each carbon atom."
17.
Boron and aluminium are both in group III of the periodic table. Which statement is true for these two elements?
Correct Answer
B. Both elements contain 3 electrons in the outermost shells.
Explanation
Both ions of the elements have the 3+ charge.
18.
Which statement about the change in properties of the elements from left to right across a period is correct?
Correct Answer
A. The elements change from being metals to non-metals.
Explanation
As you move from left to right across a period in the periodic table, the elements tend to change from being metals to non-metals. This is because the properties of elements are determined by their electron configurations, and as you move across a period, the number of valence electrons increases. Metals tend to have fewer valence electrons and non-metals tend to have more valence electrons. Therefore, as you move from left to right across a period, the elements transition from having metallic properties to having non-metallic properties.
19.
Allotropes are of...
Correct Answer
A. The same element and have similar properties
Explanation
Allotropes are different forms of the same element that exhibit distinct physical and chemical properties. Despite their differences, allotropes share some common characteristics due to their elemental composition. Therefore, they are of the same element and have similar properties.
20.
If Fluorine were mixed with Sodium Chloride, what would be the outcome?
Correct Answer
C. Sodium Fluoride and Chlorine
Explanation
Fluoride would displace chloride in an equation because it is in a higher period of group VII, making it more reactive.