Question

annotation requires the following

1. number paragraphs
2. write a summary sentence for each paragraph
3. circle vocabulary words and underline definition, circle and define words you dont know
4. make one connection, question, or ah ha moment from the text

chemical bonds in compounds
when a compound such as salt, sugar, copper sulfate, or glucose are formed,
the elements in each compound are held together by what are called chemical bonds. a chemical
bond is a force of attraction between two atoms. recall that electrons are the negatively
charged part of an atom that move around the nucleus. atoms are able to transfer (give) or
share electrons between each other and those chemical bonds cause an attraction.
recall that electrons move around the nucleus of an atom. this outer
\cloud\ of the atom has layers and there are only a certain number of electrons that can fit in
each layer. the first layer can hold two electrons, the second layer can hold eight electrons, the
third can hold eighteen electrons, and so on. these atoms naturally want to have full cloud
layers. when atoms that are lacking electrons come into contact with other atoms, they
naturally want to give or gain electrons to balance out.
a type of bond where an atom gives, or transfers, one or more electrons to
another atom is called an ionic bond. when an atom has the same number of protons (positive
charge) and electrons (negative charge), the atom remains neutral (no charge). however, once an
atom loses one or more electrons (the negative charge), the atom itself becomes positively
charged. an atom with a charge is called an ion. ions do not have the same number of electrons
as they do protons. the atom that loses an electron is called a positive ion and the atom that
receives the extra electron now has a negative charge and is called a negative ion. these two ions
attract each other because opposite forces (positive and negative) attract and form a bond. this
is how compounds are created.
another way elements are bonded together is through a covalent bond.
covalent bonds share electrons rather than giving them away or taking them. electrons are
always shared in pairs. a good example of a covalent bond is water (h2o). the electrons (negative
charge) from two hydrogen atoms and the electrons from one oxygen atom are attracted to
the positive charge held in the nuclei of each other. this attraction allows the atoms to be held
together to form a compound (water).
in the world around us, there are millions of chemical compounds. scientists
like to classify (organize into groups based on similar properties) chemical compounds into two
groups based on their bond type: ionic compounds and covalent compounds. as the names suggest,
ionic compounds are the compounds formed with ionic bonds and covalent compounds are
compounds formed with covalent bonds. ionic compounds (such as sodium chloride, or table salt)
tend to be brittle, have a high melting point, be arranged in a crystalline pattern, and are in a
solid state in room temperature. many of them can be dissolved in water. covalent compounds
(such as water and wax) often have a lower melting point and many are not water soluble
(although some, like sugar, are an exception).

Answer:

1. Number Paragraphs

1. When a compound such as salt, sugar, copper sulfate, or glucose are formed, the elements in each compound are held together by what are called chemical bonds. A chemical bond is a force of attraction between two atoms. Recall that electrons are the negatively charged part of an atom that move around the nucleus. Atoms are able to transfer (give) or share electrons between each other and those chemical bonds cause an attraction.
2. Recall that electrons move around the nucleus of an atom. This outer “cloud” of the atom has layers and there are only a certain number of electrons that can fit in each layer. The first layer can hold two electrons, the second layer can hold eight electrons, the third can hold eighteen electrons, and so on. These atoms naturally want to have full cloud layers. When atoms that are lacking electrons come into contact with other atoms, they naturally want to give or gain electrons to balance out.
3. A type of bond where an atom gives, or transfers, one or more electrons to another atom is called an ionic bond. When an atom has the same number of protons (positive charge) and electrons (negative charge), the atom remains neutral (no charge). However, once an atom loses one or more electrons (the negative charge), the atom itself becomes positively charged. An atom with a charge is called an ion. Ions do not have the same number of electrons as they do protons. The atom that loses an electron is called a positive ion and the atom that receives the extra electron now has a negative charge and is called a negative ion. These two ions attract each other because opposite forces (positive and negative) attract and form a bond. This is how compounds are created.
4. Another way elements are bonded together is through a covalent bond. Covalent bonds SHARE electrons rather than giving them away or taking them. Electrons are always shared in pairs. A good example of a covalent bond is water (H₂O). The electrons (negative charge) from two hydrogen atoms and the electrons from one oxygen atom are attracted to the positive charge held in the nuclei of each other. This attraction allows the atoms to be held together to form a compound (water).
5. In the world around us, there are millions of chemical compounds. Scientists like to classify (organize into groups based on similar properties) chemical compounds into two groups based on their bond type: ionic compounds and covalent compounds. As the names suggest, ionic compounds are the compounds formed with ionic bonds and covalent compounds are compounds formed with covalent bonds. Ionic compounds (such as sodium chloride, or table salt) tend to be brittle, have a high melting point, be arranged in a crystalline pattern, and are in a solid state at room temperature. Many of them can be dissolved in water. Covalent compounds (such as water and wax) often have a lower melting point and many are not water soluble (although some, like sugar, are an exception).

2. Summary Sentence for Each Paragraph

1. This paragraph introduces chemical bonds, defining them as the force of attraction between atoms, and explains that atoms can transfer or share electrons to form these bonds.
2. It explains the electron - cloud layers of atoms and the tendency of atoms to gain or lose electrons to achieve full electron - cloud layers.
3. The paragraph defines ionic bonds, explains how ions are formed when atoms gain or lose electrons, and how positive and negative ions attract to form compounds.
4. It defines covalent bonds as a way of bonding where electrons are shared (using water as an example), and explains how this sharing holds atoms together to form compounds.
5. This paragraph classifies chemical compounds into ionic and covalent compounds based on their bond types, and describes the general properties of each type of compound.

3. Circle Vocabulary Words, Underline Definitions, Circle and Define Unknown Words

• Circle Vocabulary Words: chemical bond, electron, ionic bond, ion, positive ion, negative ion, covalent bond, classify, ionic compounds, covalent compounds
• Underline Definitions:
• A chemical bond is a force of attraction between two atoms.
• An ionic bond is a type of bond where an atom gives, or transfers, one or more electrons to another atom.
• An ion is an atom with a charge.
• A covalent bond is another way elements are bonded together (where electrons are shared).
• Classify means to organize into groups based on similar properties.
• Ionic compounds are the compounds formed with ionic bonds.
• Covalent compounds are compounds formed with covalent bonds.
• Circle and Define Unknown Words (assuming some basic level, if any):
• Brittle (circle): hard but liable to break or shatter easily.
• Crystalline (circle): having a definite internal structure of atoms or molecules, forming a crystal - like pattern.
• Soluble (circle): capable of being dissolved, especially in water.

4. Make one connection, question, or ah - ha moment from the text

• Connection: I know that table salt (sodium chloride) is an ionic compound. Now I understand why it has a high melting point and can dissolve in water, as the text says ionic compounds have these properties.
• Question: Why do some covalent compounds like sugar dissolve in water even though most covalent compounds are not water - soluble?
• Ah - ha moment: I now understand that the difference in how atoms share or transfer electrons (covalent vs ionic bonds) leads to different properties in the compounds they form, like melting point and solubility.