Chem Homework Questions Lessons 9-13

The nuclear model and the solar system model both show atoms with electrons circling the nucleus. A. How do these two models differ? B. How are these two models similar? C. How can you refine the solar system model so that the atoms do not look flat?

A. the solar system model has electron shells the nuclear model does not B. They both have a nucleus and electrons orbiting it C. Make the model 3D

Name two elements that have similar properties to those of beryllium (Be) and have average atomic masses higher than 130.

Barium (Ba) and radium (Ra)

Why does carbon (C) have a larger mass than boron (B) even though they each have six protons?

Because carbon has more protons

Which of these elements are nonmetals? A. Bromine (Br) B. Carbon (C) C. Boron (B) D. Thallium (Tl) E. Phosphorus (P) F. Aluminum (Al)

Bromine

Hydrogen and helium are different elements. How can you use the plum pudding model to show how atoms of the two elements might be different from one another?

By showing that they have different amounts of electrons

Which two of these elements are the least reactive? Explain your thinking. A. Chlorine (Cl) B. Barium (Ba) C. Copper (Cu) D. Rubidium (Rb) E. Potassium (K) F. Mercury (Hg)

Copper and Mercury because they are the elements closest to the middle of the periodic table

If you want to identify an element, what one piece of information would you ask for? Explain your thinking.

I would ask for the atomic number because it represents the element

If you have a sample of atoms and each atom has 12 protons in its nucleus, which element do you have?

Magnesium (Mg)

Th ancient Greeks claimed that atoms were the smallest pieces of matter. Were they correct? Explain your thinking.

No because electrons, protons, and neutrons are all smaller

Can you make jewelry out of each of the elements listed below? Explain your thinking. A. Copper (Cu) B. Neon (Ne) C. Sodium (Na) D. Platinum (Pt)

No not Neon. Neon is a gas and not a metal meaning it can't be shaped as easily.

List three properties of the elements that are useful in sorting the elements.

Properties, reactivity, atomic mass

Positive and negative charges are attracted to one another. Which of the following are attracted to a negative charge: an electron, a proton, a neutron, a nucleus, an atom? Explain your thinking.

Protons because they are positively charged and would be attracted to a negative charge

Choose two different properties and describe how they vary across a period.

Reactivity: Reactivity gets less reactive as you go left to right Mass: The Mass gets bigger as you go left to right

Do you expect carbon (C) to be more similar to nitrogen (N), oxygen (O), or silicon (Si)?

Si because they are in the same column meaning they have similar reactivity and chemical formulas of compounds

Give an example that shows how science is a process of gathering and refining models.

The atom was something that required multiple experiments and theories through hundreds of years to become what they are today

Explain the differences between atomic number and atomic mass.

The atomic number is how many protons an atom has while the mass is how many protons and neutrons a atom has

What evidence caused Rutherford to change Thompson's plum pudding models into the nuclear model?

The existence of a positively charged nucleus as evidenced by the gold foil and laser experiment

What evidence caused Bohr to change Rutherford's nuclear model into the solar system model?

The existence of electron shells as evidenced by the elements giving off certain colors after being exposed to flame or electric fields

What evidence caused Thompson to change Dalton's solid sphere model into the plum pudding model?

The existence of negatively charged particles in the atoms as evidenced by zapping atoms with electricity and creating a cathode ray

What does the atomic number tell you?

The number of protons

What does the atomic mass tell you?

The number of protons and neutrons

Describe how reactivity changes as you go down Group 1A.

The reactivity becomes more violent

How are potassium-39, potassium-40, and potassium-41 different from each other?

They are different because of their mass and neutrons

Which of these elements are solids? A. Fluorine (F) B. Titanium (Ti) C. Lead (Pb) D. Oxygen (O) E. Potassium (K) F. Silicon (Si)

Titanium, Lead, Potassium, Silicon

Explain the difference between the average atomic mass given on the periodic table and the mass of an atom.

the average atomic mass is all the atoms of an elements average mass while the mass of an atom is the mass of a singular atom