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An example would be the bond between two hydrogen atoms to form hydrogen gas.
The alkaline earths are the second group (column) in the periodic table. Atoms of these elements form ions with a +2 charge. Knowing the usual valence of elements in a group helps when it comes to predicting the compounds that can be formed.
Transition metals can have different valences, so it's important to list the valence in a compound name.
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covalent, dinitrogen tetroxide
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covalent, nitrogen tetroxide
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ionic, nitrogen oxide
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ionic, dinitrogen oxide
Nonmetals form covalent bonds with each other. Rather than call any combination of nitrogen and oxygen "nitrogen oxide", you should specify how many atoms of each type are present.
Nonmetals form covalent bonds. Since the electronegativity values are not identical, you know it's a polar bond.
Answer this by looking up the atomic number (number of protons) on the periodic table. The number of protons and electrons is not the same, so you're dealing with an ion. If there are more protons than electrons, there's a net positive charge. If there are more electrons than protons, it's an ion with a negative charge.
Polyatomic ions are groups of atoms bound together that act as a cation or anion to form bonds and make compounds. To answer this question, you need to know the formula of a nitrate.
The tri- prefix in the name means "three".
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loses 2 electrons to form a magnesium ion with a 2- charge
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gains 2 electrons to form a magnesium ion with a 2- charge
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loses 2 electrons to form a magnesium ion with a 2+ charge
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gains 2 electrons to form a magnesium ion with a 2+ charge
Magnesium and other alkaline earth atoms form cations with a 2+ charge. To get that positive charge, you need 2 more protons than electrons.
The electron dot diagram shows how many lone electron pairs are present, which is similar to the valence on the atom.
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You're on track to learn more about chemical bonds and how they work. Your biggest friend when it comes to understanding chemical bonding is the periodic table because it's organized to group elements with similar charges together (for example, all of the alkali metals carry a +1 charge). Electronegativity is a periodic table trend. Atoms with the same electronegativity form nonpolar covalent bonds. Atoms with similar but not identical electronegativity (two different nonmetals) form polar covalent bonds. When the electronegativity difference is large (think metals with nonmetals), you get ionic bonds.
When you balance chemical formulas, remember the electrical charges cancel out. So, if you have two positive charges, you form a neutral compound if it bonds with two negative charges.
From here, you might want to review the types of chemical bonds and how chemical formulas work. If you're ready for another quiz, see if you understand the basics about atoms and their parts.
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Bravo! You understand how chemical bonds form and how electrons are transferred or shared to form ions and compounds. If you're ever in doubt about the type of bonds formed between atoms, look at their position on the periodic table. Atoms with the same electronegativity (like two oxygen atoms) form nonpolar covalent bonds. Atoms with close electronegativity values (like two nonidentical nonmetals) form polar covalent bonds. If the electronegativity difference is large (between a metal and a nonmetal) then ionic bonds form.
From here, you can test yourself to see if you know the trends in the periodic table or you might wish to review the types of chemical bonds.
If you're ready for another quiz, find out which type of mad scientist you are or you can practice naming ionic compounds.