True or false: Elements can be atoms OR molecules?
True. Some elements bond with themselves in nature (like O2), some elements exist as single atoms (like Ne)
Why does argon not react with other elements?
Ar is a noble gas. Noble gasses have a full valence shell, so they are energetically stable
Which two subatomic particles have an approximately equal mass?
Protons and neutrons weigh about 1 amu
How many valence electrons does oxygen have?
Oxygen (O) is in group 16, so it has 6 valence electrons
How many protons does sulfur have?
Sulfur's atomic number is 16, so it has 16 protons
What is another name for a homogenous mixture?
A solution
Draw a particle diagram of a liquid solution
Solutions are homogeneous mixtures. Should have two compounds/elements. Molecules flow but at bottom of container.
What is matter?
Anything that has mass and volume
How many energy levels does phosphorus have?
Phosphorous (P) is in period 3, so it has 3 energy levels
What is the difference between an element and a compound?
Elements are composed of one type of atom, compounds two or more types of atom
In a chemical change, what happens to the organization of the atoms?
Chemical bonds between atoms are broken and new bonds form. Atoms rearrange.
How many electrons does a neutral atom of calcium have?
Calcium's atomic number is 20, so it has 20 protons. A neutral atom has the same number of protons and electrons, so 20.
List 3 signs of a chemical change
Heat, light, color change (usually), bubbles, new substance
Metal alloys are... elements, compounds, homogenous mixtures, or heterogenous mixtures?
Homogeneous mixtures. The metals are not bonded together
Which is a chemical change: boiling water, mix dye + water, rust, paint chipping
Rust is a chemical change. The color changes and you need a chemical process to reverse it.
Which is a chemical change: chopping wood, leaves changing color, increasing temp of solution, distilling gasoline
Leaves changing color. The chlorophyll molecules break down into component elements.
Explain why a state of matter change is a physical change
Physical changes result in a decrease, increase, or spread of molecules. For example, when ice melts into water, the H2O molecules do not change.
Which element is brittle at room temp: Potassium, Calcium, Sulfur, Gold, Aluminum
Sulfur, because it is a nonmetal. We saw this in the metals, nonmetals, metalloids lab.
Which family of elements is most electrically conductive?
Metals
The periodic table is organized by...
Increasing atomic number
In a physical change, what happens to the organization of the atoms?
Structure of the element or compound stays the same.