Bonding Model: When At Least Two Atoms Are Joined ✓ Solved
Bonding Model 1. When at least two atoms are joined together
A molecule is formed when at least two atoms are joined together by bonds. A compound is specifically formed from the bonding of atoms from at least two different elements. A line between two atoms indicates they are joined by a covalent bond. A covalent bond is formed by the sharing of two electrons. The straight line represents these electrons. Electrons are tiny particles with a negative charge. Every atom of each unique element has a specific number of electrons. For example, every hydrogen atom has one electron. In the case of a double covalent bond, two lines represent the two electrons being shared, which join the atoms together in the molecule glycine.
In some cases, the electrons are not shared. In sodium chloride (NaCl), the chloride anion has extra electrons, giving it an overall negative charge, while the sodium cation has too few electrons, resulting in an overall positive charge. The association between Na+ and Cl- is called an ionic bond.
Based on these concepts, answer the following questions:
1. Define the word molecule using the words atoms and bond.
2. How many electrons would you expect between the carbon and oxygen atoms joined with a double covalent bond in Figure 2.1?
3. In the molecule glycine, there are two different carbon atoms.
a. How many bonds are being made with each of the two carbon atoms?
b. How many electrons are represented by the bonds surrounding each individual carbon atom?
4. NaCl does not have a covalent bond; rather, it has an ionic bond. What seems to be holding the NaCl molecule together?
5. In Figure 2.4, why is there only one electron in the blue box drawn around the hydrogen? Include a reference to the periodic table in your answer.
6. How many electrons are inside the box drawn around the oxygen in Figure 2.4? How is this consistent with oxygen’s group number on the periodic table?
7. Based on the pattern of box drawing shown in Figure 2.4, how are lone pairs allocated when assigning electrons for counting?
8. Complete the image below by drawing boxes around each atom in the molecule and including the electrons that belong to that atom. Also, complete the table that follows.
9. Study Figure 2.5 and provide:
- An example of a molecule that is held together with covalent bonds.
- An example of a molecule held together by ionic bonds.
- An example of a molecule held together by both ionic bonds and covalent bonds.
- An example of an organic molecule and an inorganic molecule.
10. Calcium citrate is made with two citrate molecules and three calcium ions. Explain why this is necessary for the compound to be neutral.
11. In Figure 2.6, discuss the relation between electron counts:
a. Why are 6 electrons okay for an oxygen atom, but 7 is too many?
b. How many electrons would be too many for a nitrogen atom?
c. How many electrons would be too few for a nitrogen atom?
d. Discuss how your answer to (c) explains the structure of ammonium chloride and the positive charge on nitrogen.
12. Explain why calcium citrate might also be referred to as the calcium salt of citric acid.
Paper For Above Instructions
Understanding Molecular Formation and Bonding Types
Molecules are essential building blocks of matter, defined as groups of at least two atoms bonded together. The atoms within these molecules can be of the same element or different elements. A compound is specifically a molecule that consists of at least two different elements, such as water (H2O) composed of hydrogen and oxygen.
Covalent bonds and ionic bonds are two prominent types of bonds that facilitate the interaction between atoms. Covalent bonds are formed through the sharing of electrons between atoms. For instance, in a double bond between carbon (C) and oxygen (O), the atoms share two pairs of electrons, leading to a stable connection. In contrast, sodium chloride (NaCl) exemplifies an ionic bond, where sodium (Na) donates an electron to chlorine (Cl), leading to a positive charge on sodium and a negative charge on chlorine, creating an electrostatic attraction.
1. A molecule is defined as a combination of two or more atoms connected by chemical bonds.
2. Between a carbon and oxygen atom bonded by a double covalent bond, we would expect to find four electrons being shared.
3. In glycine, the two different carbon atoms (C1 and C2) make two and four bonds, respectively. Carbon 1 typically forms three bonds, while Carbon 2 forms four bonds. Each carbon atom holds two electrons from covalent bonds.
4. The NaCl molecule is held together by the electrostatic attraction between the positively charged sodium cation and the negatively charged chloride anion.
5. The hydrogen atom in Figure 2.4 has one electron because it is in Group 1 of the periodic table, which means it contributes only one electron during bonding.
6. The oxygen atom has six electrons inside the box in Figure 2.4, consistent with its position in Group 6 of the periodic table.
7. Lone pairs are unshared electron pairs that belong to a specific atom; they are counted as part of that atom's total electron contribution but are not used in bonding.
Chemical Structures and Their Implications
Figure 2.5 illustrates various compounds categorized by their bonding types. For example, glucose represents an organic compound held together by covalent bonds, while sodium chloride exemplifies an ionic compound. Calcium citrate serves as a unique example showcasing both covalent and ionic bonds, participating in the interaction of both types, providing unique characteristics to the compound.
10. Calcium citrate consists of two citrate molecules and three calcium ions to ensure overall neutrality. The negatively charged citrates can balance the positively charged calcium ions, maintaining an electrically neutral compound.
11. a. Six electrons are sufficient for an oxygen atom due to its capacity to form two covalent bonds, while seven exceeds this capacity, causing a negative charge. b. A nitrogen atom can have a maximum of five electrons in its valence shell. c. Too few electrons for nitrogen means having fewer than three, resulting in a positive charge in compounds like ammonium chloride. d. This illustrates why nitrogen acquires a positive charge in ammonium chloride as it accepts electrons from neighboring ions.
12. Calcium citrate may be described as the calcium salt of citric acid since it results from the interaction of citric acid’s anions and calcium cations, reflecting the compound's ionic nature in addition to its covalent bonds.
References
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