Atoms 1
True or False: The number of electrons in a neutral atom is always equal to the number of protons.
False
What is the building block of all matter?
During boiling, a liquid changes into a _________.
Gas
Phineas and Ferb did an episode with a song about an Aglet. What is an Aglet?
The end of a shoelace
What is an endothermic reaction?
Heat entering
An atom of nitrogen has a mass number of 14 and an atomic number of 7. How many neutrons does it have? Why?
14 - 7 = 7
Mass number is protons + neutrons
Atomic number only the number of protons
If an atom has 12 neutrons, 11 protons and 11 electrons and a mass number of 23, what is it's atomic number?
11
Compare the speed of particles in a gas and a liquid. Which has faster-moving particles?
Gas because it has more thermal energy?
What does a flat section on a heating curve represent?
a phase change, no change in temperature
What is an exothermic reaction?
If an atom has 15 protons and 15 electrons, what is its charge? Why?
0, protons and neutrons cancel each other out
protons = positive
electrons = negative
Fill in the blanks: The mass number of an atom is the sum of its _________ and _________.
protons and neutrons
As a solid is heated, what happens to the motion of its particles?
Speed up
What phase changes occur when you add heat?
melting and evaporating
Is melting ice endothermic or exothermic? why?
Endothermic, heat going in
(endo = enter)
The atomic number of an element is always equal to the number of _________
protons
A neutral atom has 20 protons and 40 electrons. What is the atomic number of this atom?
20
Fill in the blanks: When a gas cools, its particles move _________, and the gas may become a _________.
slow down, liquid
What phase changes occur when you remove heat?
Condensation and freezing
Which reaction releases heat: burning wood or boiling water? Why?
Burning wood because heat is being released
What are the three subatomic particles that make up an atom, and where are they located?
Protons, neutrons, and electrons; nucleus ( p / n ) and electron cloud (e)
A chlorine atom has 17 protons, 18 neutrons and 17 electrons. What is its mass number?
Include the unit
35 amu
Selena Gomez got famous from this Disney TV Show. 1. What was the name of the show? 2. What was her name in the show?
1. Wizards of Waverly Place
2. Alex Russo
What is a heating curve? What is a cooling curve?
Heating = endothermic, heat entering
Cooling = exothermic, heat exiting
Is freezing ice endothermic or exothermic? why?
Exothermic, heat going out
(Exo = Exit)