chemistry 1 Flashcards
(34 cards)
What is an atom?
The smallest unit of matter that still retains the properties of an element.
What is the charge and mass characteristics of neutrons?
No electrical charge, has mass, number can change.
What is the charge and role of protons in an atom?
Positive charge, has mass, determines identity of element.
What is the charge and mass characteristics of electrons?
Negative charge, negligible mass, number can change.
What two things does the atomic number represent?
The number of protons in an atom & element identity
What is the mass number (atomic weight)?
The total number of protons and neutrons in an atom.
Where are electrons found in an atom?
In orbitals, within electron shells, around the nucleus.
What is the maximum number of electrons per orbital?
2 electrons.
How are the electron shells calculated?
2n^2
What are electron shells?
Groups of orbitals in which electrons are arranged.
What is the maximum number of electrons in the first shell?
2 electrons.
What is the maximum number of electrons in the second shell?
8 electrons.
What are valence electrons?
Electrons found in the outermost shell of an atom.
Fill in the blank: Atoms try to fill shells by forming _______ or forming _______.
covalent bonds, ions
What are covalent bonds?
A pair of electrons shared by two atoms.
What is a molecule?
2 or more atoms joined by covalent bonds.
How many pairs of electrons shared represent a double bond?
2 pairs.
What is an ionic bond?
An attraction among oppositely charged ions.
What happens to electrons in ionic bonding?
Electrons are transferred from one atom to another.
What are the two characteristics of polar molecules?
partial charge; unequally shared
True or False: Water is a polar molecule.
True.
What are the 5 properties of water?
- Cohesion
- Surface tension
- Density
- Solvent properties
- Heat capacity
What is cohesion?
The attraction between water molecules.
What causes surface tension in water?
The cohesive forces between water molecules; the skin on the water
