Science Unit 4 answers JPJ
List the similarities and differences between ionic, covalent, and metallic bonds.
-all head attraction from atoms nucleus -all atoms combine together
Name the physical properties that many ionic compounds share.
-form from crystals -hard or brittle -conduct electricity while dissolve in water
How many valance electrons does a nitrogen atom have?
5
Sulfur (S) is in Group 16 of the periodic table. How many valance electrons does an atom in Sulfur have?
6
What is a chemical change?
A change that occurs when one or more substances change into entirely new substances with different properties
What is an element?
A substance that cannot be separated or broken down into simpler substances by chemical means
What is a chemical bond?
An interaction that holds atoms or ions together
Imagine you need to make a model that shows the locations of the parts of a sodium atom. Explain which type of model you would use.
Bohr, it would be easy to show, and it would be easy to label it
Name the 4 properties that most ionic compounds share.
Electrical conductivity crystal lattice structure brittleness solubility in water
Name the 3 properties that most metallic compounds share.
Good electrical conductors malleable ductile
Name the 4 properties that most covalent compounds share.
Low solubility in water low melting point low boiling point poor electrical conductivity
How does a metallic bond compare to an ionic or covalent bond in terms of strength?
Metallic bonds are weak compared to ionic or covalent bonds because the electrons move freely around and in the ionic or covalent bond the electrons are tightly packed together
How can you explain that atoms are not created or destroyed during a chemical change?
The atoms are rearranged to make new substances with different properties
Explain how an ionic compound can have a neutral charge.
Their electrons cancel out, so if a metal atom loses electrons, it is equal to the amount of electrons the non-metal gains
Why are atoms of Lithium, Sodium, and Potassium almost never found alone in nature?
They have 1 valance electron so they go and look for another one to join
What is a negative ion?
When an atom gains at least one electron, and then has more electrons than protons
What is a positive ion?
When an atom loses at least on electron, and then has fewer electrons than protons
How does the electron "sea" help metal bend without breaking?
When it is bent the electron sea makes it harder to bend more
What is a metallic bond?
a bond formed by the attraction between positively charged metal ions and the electrons around them
What is an covalent bond?
a bond formed when atoms share one or more pairs of electrons
What is a molecule?
a group of atoms that are held together by chemical forces; a molecule is the smallest unit of a compound that keeps all the properties of that compound
What are valance electrons?
an electron that is found in the outermost shell of an atom and that determines the atom's chemical properties
What are chemical bonds?
an interaction that holds atoms or ions together
A chemical bond joins ________ together in a water molecule.
atoms
Which of the following can happen during a chemical change? a. atoms change into new types of atoms b. bonds break, and new bonds form c. nuclei of atoms break apart and combine d. all of the electrons in the atom are lost
b
Metals _____ be reshaped without breaking.
can
What is an ion?
charge of an atom depending on the number of protons and electrons
bond formed by atoms sharing electrons
covalent bonds
describe the role of electrons in the formation of a covalent bond.
electrons are shared and fill the outermost level
Name one fact of a covalent bond.
electrons are shared between atoms
Why might metallic bonding be weak compared to ionic and covalent bonding?
electrons move freely and the ionic and covalent electrons don't
Name one fact of an ionic bond.
electrons transfer between atoms
True or False. A Bohr model is the best choice to show how atoms are arranged in molecules.
false
forms when an atom gains or loses one or more electrons
ion
In general, covalent compound have _____ boiling point.
low
Which is a better conductor of electric current: a solid ionic compound or a melted ionic compound?
melted ionic compound
What are the 3 ways in which an atom can form bonds with other bonds?
metallic bonds ionic bonds covalent bonds
group of atoms held together by chemical bonds
molecule
How would a Bohr model of a neon atom differ from the model of nitrogen?
nitrogen has 3 less electrons, neutrons, and protons
Ionic bonds usually form between a positively charged metal ion and a negatively charged _________ ion.
nonmetal
The 4 valance electrons of a carbon atom are in its _____________ energy level
outermost
Name one fact about a metallic compound.
outermost energy level's overlap
Describe the difference of a positive and negative ion.
positive- loses electrons negative- gains electrons
What is an ionic bond?
the attractive force between oppositely changed ions, which form when electrons are transferred from one atom to another
What is an atom?
the smallest unit of an element that maintains the properties of that element
How can you tell that atoms are not created or destroyed by the chemical change?
they are connected by chemical bonds
How is the position of electrons involved in metallic bonding different from the position of electrons that form ionic and covalent bonds?
they are in different places on their energy level
True or False. Atoms are rearranged during a chemical change when bonds break and form.
true
True or False. The atom above is reactive because its outermost energy level is not full.
true
Explain whether or not nitrogen atoms will form bonds with other atoms.
yes, they will form covalent bonds
