Question | Answer |
What does an atom consist of? | A nucleus, surrounded by one or more electrons. |
What is a nucleus? | The tiny central core of an atom that contains protons and neutrons. |
What are protons? | A positive electrical charge, denoted by the + sign. |
What are neutrons? | No charge particles, they are neutral. |
What are electrons? | Electrical particles that move in the space around the nucleus, moving rapidly in all directions. |
What are valence electrons? | Electrons that are farthest from the nucleus. # of valence elctrons determins whether or not an atom will bond with another atom. |
What is an electron dot diagram? | It includes the symbol for an element surrounded by dots. Each dot stands for one valence electron. |
How is a chemical bond formed? | It forms between two atoms when valence electrons move between them. The valence electons may be transferred or shared between them. |
Why is the electrical charge on an atom zero, or neutral? | Because the number of protons and electrons is the same, so the charges cancel each other out. |
Explain why electrons make up much of an atoms volume but not much of its mass. | The protons and neutrons are 2000 times bigger than the electons, so they make up most of the mass. The electons move around the nucleus taking up the space, or volume of an atom. |
What is an atomic number? | The number of protons in the nucleus of an atom. |
What is an family? | Atoms in the same column up to down |
What is a period | Atoms in the same row left to right |
What group 18 called | noble gasses or innert, inactive. they don't react easily with other atoms. |
What is group 17 called | The halogen family are reactive nonmetals that are very reactive because they have 7 valence electrons. |
How are the elements in the same family alike | They have the same number of valence electrons |
What is group 1 called | Alkali family is the most reactive family out all and are very highly reactive because it has only 1 valence electron |
What is an ion? | An atom or group of atoms that have become electrically charged. |
How does an atom become an ion? | When an atom gains an electron it becomes negatively charged. When an atom loses an electron, it becomes positively charged. |
How does negative and positive electric charges attract? | They have to be opposites to attract each other. |
What is an ionic bond? | The attraction between two oppositely charged ions. |
Why are compounds electrically neutral? | When ions bond they do so in such a way that their charge of each balances out the charge of the compound. ie. MgCl2 Mg is +2 charge, Cl is -1 charge, you need 2 Cl to balance Mg's +2 |
What are polyatomic ions? | Ions that are made up of more than one atom. |
How does a polyatomic ion combine with another ion? | In the same way that ions attract, with negative and positive charges canceling out each other, polyatomic ions have an overall positive or negative charge that can bond with an ion of the exact opposite charge. |
What are three characteristic properties of ionic compounds? | Crystal shape, high melting points, and electrical conductivity. |
What is a crystal? | When ions form an orderly three dimensional arrangement or pattern. |
How do ionic compounds attract with ions? | With ions near it that have an opposite charge. |
What kind of atom has a name change when it becomes an ion? | If the negative ion is an element, the end of its name changes to -ide. ie. MgO is magnesium Oxide |
What is a covalent bond? | A chemical bond formed when two atoms share electrons, usually between two or more nonmetals. |
How does a covalent bond work? | Both atoms attract the two shared electron at the same time. |
What is a double bond? | When two pairs ofelectrons are shared. |
What do molecular compounds consist of? | Molecules having covalently bonded atoms. |
Which has stronger bonds, molecular (covalent) or ionic bonds? | Ionic bonds are stronger. |
Which is a better conductor of electricity? Molecular or Ionic compounds? | Ionic compounds conduct electricity better. |
Why are molecular compounds poor conductors? | Because there are no charged particles that are available to move, so electricity does not flow. |
Why do some atoms in covalent bonds have slight negative or positive charge? | Some atoms pull hareder on the shared electron, causing the electrons to move closer to one atom, resulting in a slight electrical charge. |
What makes a covalent bond polar? | When electrons are shared unequally in a covalent bond. |
When is a covalent bond nonpolar? | When electrons are shared equally. |
When is a molecule nonpolar? | If it contains polar bonds that cancel each other. |
What is a polar molecule? | When one end of the molecule is positive and the other end is negative. |
In terms of electrons, how is a covalent bond different from an ionic bond? | In ionic bonds, electrons are transferred from one atom to another, and in a covalent bond, electrons are shared. |