Unit 4 Supplemental Pre Test

The Lewis dot structure is a representation of an atom's valence electrons using dots around the chemical symbol. The number of dots corresponds to the number of valence electrons. This structure helps to understand the bonding and electron distribution in molecules. Therefore, when a chemical symbol is surrounded by a number of dots corresponding to the number of valence electrons, it is a Lewis dot structure.

Ionic bonds occur when atoms are bound together by the attraction between oppositely charged ions. In an ionic bond, one atom donates electrons to another atom, resulting in the formation of positive and negative ions. These ions then attract each other, creating a strong bond. Ionic bonds typically occur between metals and nonmetals, where the metal atom loses electrons to become a positively charged ion, and the nonmetal atom gains those electrons to become a negatively charged ion. This electrostatic attraction between the ions is what holds them together in an ionic bond.

A covalent bond is a type of chemical bond where atoms are bound together by sharing electrons. In this type of bond, the electrons are shared between the atoms involved, allowing them to achieve a more stable electron configuration. This sharing of electrons creates a strong bond between the atoms, resulting in the formation of molecules. Covalent bonds are typically formed between nonmetal atoms, as they have a high tendency to gain, lose, or share electrons in order to achieve a stable electron configuration.

Electrons have a negative charge because they are subatomic particles that carry a fundamental unit of negative electric charge. This charge allows electrons to be attracted to positively charged particles, such as protons, and repelled by other negatively charged particles.

The name given to the outermost electron(s) is valence electrons. Valence electrons are the electrons located in the outermost energy level or shell of an atom. These electrons are involved in chemical bonding and determine the reactivity and chemical properties of an element.

Positively charged ions, called cations, result from the loss of electrons. When an atom loses one or more electrons, it becomes positively charged because there are more protons than electrons. This creates an imbalance of positive and negative charges, leading to the formation of cations. An example is when a sodium atom loses one electron, it forms a sodium cation with a positive charge.

An ionic bond forms when a cation, which is a positively charged ion, transfers its extra electron to an anion, which is a negatively charged ion, who needs it. This transfer of electrons results in the formation of a strong electrostatic attraction between the two ions, creating an ionic bond. This type of bond typically occurs between a metal and a nonmetal, where the metal donates its electron(s) to the nonmetal, resulting in the formation of a stable compound.

Ions of opposite charge are attracted to each other easily, which is why they form a specific pattern called a crystal lattice.

Ionic bonds are formed when there is a transfer of electrons from a metal to a nonmetal. Nonmetals have a higher electronegativity compared to metals, meaning they have a greater ability to attract and gain electrons. Metals, on the other hand, have a lower electronegativity and tend to lose electrons. Therefore, the correct answer is nonmetals as they are the ideal partners for metals to form ionic bonds.

The compound MgO2 is named magnesium oxide. This is because it consists of magnesium (Mg) and oxygen (O) atoms, with a 2:1 ratio. When naming compounds, the cation (in this case, magnesium) is named first, followed by the anion (oxygen) with the suffix "-ide". Therefore, the correct name for MgO2 is magnesium oxide.

The compound HBrO is named bromic acid or Bromic Acid.

Sodium chlorite is the correct answer because the compound NaClO is commonly known as sodium chlorite. It is a white crystalline powder that is used as a disinfectant and bleaching agent. Sodium chlorite is composed of one sodium ion (Na+) and one chlorite ion (ClO-), resulting in the chemical formula NaClO.

The compound P2O3 is named diphosphorus trioxide. The prefix "di-" indicates that there are two phosphorus atoms in the compound, and the prefix "tri-" indicates that there are three oxygen atoms. Therefore, the correct name for this compound is diphosphorus trioxide.

The compound Cr2(CO3)3 is named chromium (III) carbonate. This is because the compound contains chromium ions with a +3 charge, indicated by the Roman numeral III in parentheses after the name chromium. The compound also contains carbonate ions, which consist of one carbon atom bonded to three oxygen atoms. Therefore, the correct name for this compound is chromium (III) carbonate.

The correct chemical formula for magnesium borate is Mg3(BO3)2. The formula indicates that there are three magnesium atoms (Mg) and two borate groups (BO3) in the compound. The parentheses indicate that the borate group consists of one boron atom (B) and three oxygen atoms (O). The subscript numbers indicate the number of each element present in the compound.

Strontium dichromate is a compound composed of strontium (Sr), chromium (Cr), and oxygen (O). The correct chemical formula for strontium dichromate is SrCr2O7, which indicates that there are two chromium atoms (Cr) and seven oxygen atoms (O) for every strontium atom (Sr) in the compound.

Potassium iodide is a compound composed of one potassium ion (K+) and one iodide ion (I-), resulting in the chemical formula KI. The symbol K represents the element potassium, while the symbol I represents the element iodine. The combination of these two elements forms the compound potassium iodide.

Ionization is the process of removing or adding electrons to an atom or molecule, resulting in the formation of ions. This can occur through various means such as heating, collision, or exposure to electromagnetic radiation. The process of ionization is important in many scientific and technological applications, including the operation of batteries, the production of plasma, and the formation of chemical compounds.

Negatively charged ions, called anions, result from gain of electrons. When an atom gains one or more electrons, it becomes negatively charged and forms an anion. Anions are attracted to positively charged ions, called cations, and together they form ionic compounds.

Carbon dioxide is a compound made up of one carbon atom bonded to two oxygen atoms. The correct chemical formula for carbon dioxide is CO2.

This question is asking for an example of something, but the specific topic or concept is not provided. The correct answer is "lewis dot structure," which is a method used to represent the valence electrons of an atom in a molecule. It is a way to visualize the bonding and lone pairs of electrons in a molecule.

When an electron is added to or removed from an atom, the atom becomes an ion. This is because the addition or removal of an electron results in a change in the overall charge of the atom. If an electron is added, the atom becomes negatively charged and is called an anion. If an electron is removed, the atom becomes positively charged and is called a cation.

The compound KNO2 is called potassium nitrite. This is because the symbol K represents potassium, and NO2 represents the nitrite ion. The nitrite ion has a charge of -1, so it combines with the potassium ion, which has a charge of +1, to form a neutral compound. Therefore, the correct name for this compound is potassium nitrite.

The correct answer is tin (IV) hydroxide. This is because the compound Sn(OH)4 contains tin (Sn) in its highest oxidation state, which is +4. The Roman numeral IV represents this oxidation state. Hydroxide (OH) is the polyatomic ion that consists of one oxygen atom and one hydrogen atom, and it is responsible for the hydroxide group in the compound. Therefore, the correct name for Sn(OH)4 is tin (IV) hydroxide.

The compound ZnS is named zinc sulfide because it consists of the elements zinc (Zn) and sulfur (S). The name of a compound is determined by the elements present in it, and in this case, the compound contains zinc and sulfur, hence it is named zinc sulfide.

The compound Pb3(BO3)4 is named lead (IV) borate because it contains lead (Pb) ions with a +4 oxidation state and borate (BO3) ions. The Roman numeral IV indicates the +4 oxidation state of lead in the compound.

Silicon tetrahydride is a compound that consists of one silicon atom bonded to four hydrogen atoms. The correct chemical formula for silicon tetrahydride is SiH4.

Non-metals have a higher electronegativity compared to metals, which means they have a stronger attraction for electrons. As a result, non-metals tend to gain electrons during chemical reactions to achieve a stable electron configuration and become negatively charged ions. This is because by gaining electrons, non-metals can fill their outermost energy level and attain a more stable electron configuration, similar to the nearest noble gas.

A single covalent bond results in two shared electrons. In a covalent bond, two atoms share a pair of electrons in order to achieve a stable electron configuration. This sharing of electrons allows both atoms to fill their outermost electron shells, resulting in a more stable molecule. Therefore, a single covalent bond involves the sharing of two electrons between two atoms.

Double covalent bonds occur when two atoms share two pairs of electrons. Each pair of electrons consists of two electrons, so a double bond involves four shared electrons.

The Lewis formula for ammonia (NH3) is represented by the correct answer A. In this formula, the central nitrogen atom is surrounded by three hydrogen atoms and one lone pair of electrons. The lone pair of electrons on the nitrogen atom is represented by a pair of dots. This formula accurately depicts the arrangement of atoms and electrons in the ammonia molecule.

Triple covalent bonds result in 6 shared electrons because a triple bond consists of three pairs of electrons being shared between two atoms. Each pair of electrons counts as 2 shared electrons, so three pairs of electrons would result in 6 shared electrons.

The compound C3H8 is called tricarbon octahydride because it consists of three carbon atoms and eight hydrogen atoms. The prefix "tri-" indicates the presence of three carbon atoms, and the prefix "octa-" indicates the presence of eight hydrogen atoms. Therefore, tricarbon octahydride is the correct name for this compound.

The correct chemical formula of the compound potassium permanganate is KMnO4.

The Lewis structure for SF2 is represented by answer choice B. This is because sulfur (S) is the central atom and is surrounded by two fluorine (F) atoms. Each fluorine atom is bonded to the sulfur atom with a single bond, and there are no lone pairs on the sulfur atom. This arrangement satisfies the octet rule for both sulfur and fluorine, with each atom having a full outer shell of electrons.

Diatomic molecules are when TWO ATOMS of an element bond. O2 is a diatomic molecule because there are two atoms of oxygen.
Two atoms of Nitrogen cannot create N3 - it is not a diatomic molecule. Three atoms of Nitrogen can create N3, however - this is called a triatomic molecule.

Barium acetate is a compound composed of barium ions (Ba2+) and acetate ions (C2H3O2-). The correct chemical formula for barium acetate is Ba(C2H3O2)2, which indicates that there are two acetate ions for every barium ion.

Calcium sulfide is represented by the chemical formula CaS. In this compound, calcium (Ca) has a charge of +2 and sulfur (S) has a charge of -2. To balance the charges, one calcium ion combines with one sulfur ion, resulting in the formula CaS.

When hydrogen forms a bond with oxygen, it can NOT fit any more electrons around it, since it only has the 1st energy level. Therefore, the other 4 electrons must go on the oxygen. Unpaired electrons on the central atom will bend the atom.

The Lewis structure for Oxygen (O2) is represented by answer B. This is because Oxygen has 6 valence electrons and requires 2 more electrons to achieve a stable octet. Answer B shows the sharing of 2 electrons between the two Oxygen atoms, forming a double bond. This arrangement allows both Oxygen atoms to have a full outer shell of 8 electrons, satisfying the octet rule.

A double bond involves two pairs of electrons. This means that there are two shared electron pairs between two atoms in a molecule. In a double bond, the atoms are held together by the strong electrostatic attraction between the shared electrons and the nuclei of the atoms. This arrangement allows for a higher degree of stability and rigidity in the molecule. Therefore, the statement is true.

All ionic compounds have the metal first, and the nonmetal second. The nonmetal always ends in -IDE.
So Lithium and nitrogen would create Lithium Nitride.

Nitrogen needs 3 electrons, and one atom of Lithium can only give 1 electron.
So, there needs to be three atoms of Lithium to give 3 electrons to one atom of Nitrogen.
So, you put "3" in front of Lithium to say that there has to be 3 Lithium electrons. You don't put anything in front of Nitrogen because there is only 1 atom needed.
So, the formula will be Li3N.

Nickel is one of the elements that doesn't have only charge, but many different possible charges.
The roman numeral II means 2. If we write Nickel (II), it means Nickel with a charge of +2.
If we don't write the II, no one will know what charge Nickel actually is.
So, we write Nickel (II) Chloride.

Nickel gives off two electrons and Chlorine is only able to recieve one.
So, introduce another atom of Chlorine.
One atom of Nickel can give off two electrons and both atoms of Chlorine will recieve one each.
Since there is one atom of Nickel and two of Chlorine, we write NiCl2.

The correct chemical formula for sodium iodide is NaI. Sodium iodide is a compound composed of one sodium atom (Na) and one iodine atom (I). It is commonly used in medicine and as a reagent in chemical reactions.

Sodium and chloride do not form a covalent bond. They actually form an ionic bond. In an ionic bond, sodium donates an electron to chlorine, resulting in the formation of positively charged sodium ions and negatively charged chloride ions. Covalent bonds, on the other hand, involve the sharing of electrons between atoms.

The correct answer is "Trigonal planar." In BI3, the central atom (Boron) is surrounded by three bonding pairs of electrons and no lone pairs. This arrangement gives the molecule a trigonal planar shape, with a bond angle of approximately 120 degrees between each bond.

The compound CS4 is named carbon tetrasulfide because it consists of one carbon atom bonded to four sulfur atoms. The prefix "tetra-" indicates the presence of four sulfur atoms, while "carbon" indicates the presence of one carbon atom. Therefore, the correct name for this compound is carbon tetrasulfide.

The compound HMnO4 is named permanganic acid because the prefix "per-" indicates that the compound contains the highest possible oxidation state of manganese (+7). The -ic acid suffix indicates that the compound is an acid. Therefore, permanganic acid is the correct name for HMnO4.

Hydrogen peroxide is a compound that consists of two hydrogen atoms bonded to two oxygen atoms. The correct chemical formula for hydrogen peroxide is H2O2, as it accurately represents the composition of the compound.

Ionic solids are not good conductors of electricity. In ionic solids, the ions are held together by strong electrostatic forces of attraction, which make them stable and rigid. However, these forces also prevent the movement of ions, making ionic solids poor conductors of electricity. In order for a substance to conduct electricity, it must have free-moving charged particles, such as ions or electrons, which can carry the electric current. Therefore, the statement that ionic solids are good conductors of electricity is false.