Which contributes more to an atom’s mass—electrons or

Who advanced the idea of atoms in the early 1800s?

What causes dust particles and tiny grains of soot to move with Brownian motion?

Who first explained Brownian motion and made a convincing case for the existence of atoms?

How does the approximate number of atoms in the air in your lungs compare with the number of breaths of air in Earth’s atmosphere?

Are most of the atoms around us younger or older than the Sun?

Why can’t atoms be seen with a powerful optical microscope?

Why can atoms be seen with an electron beam?

What is the purpose of a model in science?

Where in the atom is most of its mass concentrated?

What is meant by the term nucleon?

How does the electric charge of a proton compare with the electric charge of an electron?

Since atoms are mostly empty space, why don’t we fall through a floor we stand on?

What element has the lightest atoms?

How are elements with nuclei heavier than those of hydrogen and helium formed?

What is the most abundant element in the known universe?

Where did the heaviest elements originate?

What are the five most common elements in humans?

What does the atomic number of an element tell you about the element?

How many shells are represented in the presently known periodic table?

What kind of attraction pulls electrons close to the atomic nucleus?

How does one isotope differ from another?

Why aren’t heavier elements much larger than lighter elements?

Distinguish between mass number and atomic mass.

What is a compound? Cite two examples.

What is a mixture? Cite two examples.

How does a molecule differ from an atom?

Compared with the energy it takes to separate oxygen and hydrogen from water, how much energy is released when they recombine?

How do matter and antimatter differ?

What occurs when a particle of matter and a particle of antimatter meet?

What is the evidence that dark matter exists?

Consider the following atoms: A. gold, B. copper, C. carbon, and D. silver. Consult the periodic table and rank these atoms, from most to least, by their a. mass. b. number of electrons. c. number of protons.

Rank the numbers of shells in these noble-gas atoms from most to fewest: a. Argon b. Radon c. Helium d. Neon

Rank the masses of these molecules from greatest to least

How many types of atoms can you expect to find in a pure sample of any element?

How many individual atoms are in a water molecule?

When a container of gas is heated, would you expect its molecules to speed up, slow down, or be unaffected?

The average speed of a perfume-vapor molecule at room temperature may be about 300 m/s, but you’ll find the speed at which the scent travels across the room is much less. Why?

Which of the following are pure elements: \(\mathrm{H}_{2}\), \(\mathrm{H}_{2} \mathrm{O}\), He, Na, NaCI, \(\mathrm{H}_{2} \mathrm{SO}_{4}\), U?

Which of the following is not an element: hydrogen, carbon, oxygen, water?

Your friend says that what makes one element distinct from another is the number of electrons around the atomic nucleus. Do you agree wholeheartedly, partially, or not at all? Explain.

What is the cause of the Brownian motion of dust and other small particles? Why aren’t larger objects, such as baseballs, similarly affected?

How many atoms are in a molecule of sulfuric acid, \(\mathrm{H}_{2} \mathrm{SO}_{4}\)? Text Transcription: H_2 SO_4

The mass numbers of two isotopes of cobalt are 59 and 60. (a) How many protons and how many neutrons are in each isotope? (b) How many orbiting electrons does an atom of each have when the atoms are electrically neutral?

A particular atom contains 29 electrons, 34 neutrons, and 29 protons. What is the identity of this element, and what is its atomic number?

What element results if you add a pair of protons to the nucleus of mercury? (See the periodic table.)

If two protons and two neutrons are removed from the nucleus of an oxygen atom, what nucleus remains?

What element results if two protons and two neutrons are ejected from a radium nucleus?

To become a negative ion, does an atom lose or gain an electron?

To become a positive ion, does an atom lose or gain an electron?

You could swallow a capsule of germanium without ill effects. But, if a proton were added to each of the germanium nuclei, you would not want to swallow the capsule. Why? (Consult the periodic table.)

Helium is an inert gas, which means that it doesn’t readily combine with other elements. What five other elements would you also expect to be inert gases? (See the periodic table.)

Which of the following elements would you predict to have properties most similar to those of silicon (Si): aluminum (Al), phosphorus (P), or germanium (Ge)? (Consult the periodic table.)

Which contributes more to an atom’s mass: electrons or protons? Which contributes more to an atom’s size?

A hydrogen atom and a carbon atom move at the same speed. Which has the greater kinetic energy?

In a gaseous mixture of hydrogen and oxygen gas, both with the same average kinetic energy, which molecules move faster on average?

The atoms that make up your body are mostly empty space, and structures such as the chair you’re sitting on are composed of atoms that are also mostly empty space. So why don’t you fall through the chair?

Make up a multiple-choice question that will test your classmates on the distinction between any two terms in the Summary of Terms list.

A cat strolls across your backyard. An hour later, a dog with his nose to the ground follows the trail of the cat. Discuss this occurrence from a molecular point of view.

If no molecules in a body could escape, would the body have any odor?

Where were the atoms that make up a newborn infant “manufactured”?

Discuss why equal masses of golf balls and Ping-Pong balls don’t contain the same number of balls.

Discuss why equal masses of carbon atoms and oxygen atoms don’t contain the same number of particles.

Discuss which contains more atoms: 1 kg of lead or 1 kg of aluminum.

A carbon atom, with a half-full outer shell of electrons - four in a shell that can hold eight - readily shares its electrons with other atoms and forms a vast number of molecules, many of which are the organic molecules that form the bulk of living matter. Looking at the periodic table, what other element do you think might play a role like carbon in life forms on some other planet?

In what sense can you truthfully say that you are a part of every person in history? In what sense can you say that you will tangibly contribute to every person on Earth who will follow?

What are the chances that at least one of the atoms exhaled by your very first breath will be in your next breath?

Hydrogen and oxygen always react in a 1:8 ratio by mass to form water. Early investigators thought this meant that oxygen was 8 times more massive than hydrogen. What chemical formula did these investigators assume for water?

Somebody told your friend that if an antimatter alien ever set foot on Earth, the whole world would explode into pure radiant energy. Your friend looks to you for verification or refutation of this claim. What do you say?