chem 7.1 and 7.2 quiz
How do atoms form a cation?
A cation is produced when an atom looses one or more valence electron(s)
What is an anion and how is it produced?
An anion is a group of atoms with a negative charge. They are produced when an atoms gains one or more valence electrons.
How do the ions of elements react to form a stable octet of electrons?
Atoms of metals tend to loose their valence electrons, leaving a complete octet in the next-lowest energy level. Atoms of nonmetals tend to gain/share electrons to achieve an octet.
Using calcium (Ca), explain how it forms an ion. Use information that is similar to your answer to question 9. (4 points)
Calcium is in group 2. it has 2 electrons in the outer shell. When these electrons are lost, a calcium ion Ca2+is formed
What are ions formed from the halogen elements known as?
The ions produced when atoms of chlorine and other halogens gain electrons are called halide ions
In 1916, Gilbert Lewis proposed the Octet Rule. State this rule.
The octet rule: in forming compounds, atoms tend to achieve the electron configuration of a noble gas - has only 8 electrons in the highest energy level
Why do the electron dot structures show no more than 8 electrons?
The octet rule: in forming compounds, atoms tend to achieve the electron configuration of a noble gas - has only 8 electrons in the highest energy level
notation used to illustrate the bonding in a compound
electron dot formula
the lowest whole-number ratio of ions in an ionic compound
formula unit
electrostatic forces that hold ions together in ionic compounds
ionic bond
compound composed of cations and anions
ionic compound
Which two suborbitals are needed for the Octet Rule?
s suborbital and p suborbital ex: ns^2np^6
List the three properties of ionic compounds.
1.) can conduct an electric currecn when melted or dissolved in water (electrolytes) 2.) most are crystalline solids at room temp 3.) they generally have high melting points
What are valence electrons?
Electrons in the highest energy level of an element's atoms; determines the chemical properties of an element.
Using sodium (Na), explain how Group 1A elements form ions. You may want to refer to the periodic table on pages 178-79 in the textbook and include nuclear structure and electron number in your explanation.
Sodium can loose a single electron to form + ions. When sodium looses its one electron in the outer shell, Na1+ is formed (ion)
Why is NaCl considered a formula unit rather than just a chemical formula?
There is no discrete bonding of this sodium ion to the chloride ion, so the formula for sodium chloride is expressed as a formula, not a chemical l. It is expressed as the smallest whole number ration between the Na and CI ions which is 1:1
How can we determine the number of the valence electrons in a representative element?
To find the number of valence electrons in an atom of a representative element, just look at the element's group number.
Why is the number of valence electrons present important?
Valence electrons are usually the only electrons involved in a chemical bond. Only valence electrons are shown in electron dot structures. The fewer valence electrons in an atom, the less stable it becomes.
shows the number of atoms of each element in the smallest representative unit of a substance
chemical formula