Chem Review Flashcards
A Trace Element
required only in minute amounts by living organisms
Elements cannot?
be broken down to other substances by chemical reactions
What is mass number?
the amount of protons + nuetrons
What is atomic number?
number of protons
What are electron shells?
The energy level of electrons at a characteristic average distance from the nucleus of an atom
What is a valence shell?
Where electrons are found in an atom during a chemical reation
whats van der Waals interaction
ability of atoms and molecules to stick together due to ever-changing regions of positive and negative charges
covalent bonds are…
sharing of electrons
How many covalent bonds can oxygen make
2
How do you know how many covalent bonds an atom can make?
By knowing how far away they are from a noble gas
What charge is Hydrogen
positive
What is cohesion
Hydrogen bonds can hold the atoms of a substance together
What is heat?
A measure of matter’s total kinetic energy due to motion of its molecules
What is a Calorie
the amount of heat required to raise the temperature of 1 g of water by 1 degree C
What is Evaporative Cooling
the “hottest” molecules, or the ones with the most kinetic energy, are leaving the surface as a gas.