8th Grade Physical Science Questions - Need Answers!?

Question

1. Which of the following scientists inferred that an atom's positive charge must be clustered in the nucleus?
A) Niels Bohr
B) John Dalton
C) Ernest Rutherford
D) J.J. Thomson

2. In an atom, the number of protons equals the number of
A) Nuclei
B) Electrons
C) Neutrons
D) Isotopes

3. Elements in Group 17 (the halogens) are the _____ reactive metals.

4. Elements that form diatomic molecules, or molecules of 2 atoms each, are commonly found on the ____ right side of the periodic table.

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For questions 5-7, refer to http://www.corrosionsource.com/handbook/periodic/periodic_table.gif

5. List three elements from the group containing the most reactive nonmetals.

6. In each period, how does the number of electrons in each kind of atom change from left to right between Groups 1 and 2? Explain how you know.

7. How many atoms of a Group 17 elements would be needed to react with one atom of a Group 2 element? Explain.

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Thanks.

Answer 1

1) C) Ernest Rutherford
2) B) Electrons
3) chemically (due to higher electronegativity)
4) second last goup (17th goup forms diatomic molecules)
5) halogens-Florine,Chlorine,Bromine
6)As we move from left to right atomic size decreases ,ionization energy increases and electrons are very difficult to be removed from their outer orbits
7) there are 2 atoms (1molecule) needed to react with element of group 2
example Mg + Cl2-----> 2Mgcl


all the best
7)

Answer 2

1. Which of the following scientists inferred that an atom's positive charge must be clustered in the nucleus?
A) Niels Bohr
B) John Dalton
C) Ernest Rutherford
D) J.J. Thomson

2. In an atom, the number of protons equals the number of
A) Nuclei
B) Electrons
C) Neutrons
D) Isotopes

Electrons since the atom is electrically neutral.

3. Elements in Group 17 (the halogens) are the _____ reactive metals.

4. Elements that form diatomic molecules, or molecules of 2 atoms each, are commonly found on the ____ right side of the periodic table.

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For questions 5-7, refer to http://www.corrosionsource.com/handbook/...

5. List three elements from the group containing the most reactive nonmetals.

6. In each period, how does the number of electrons in each kind of atom change from left to right between Groups 1 and 2? Explain how you know.

7. How many atoms of a Group 17 elements would be needed to react with one atom of a Group 2 element? Explain.

Right now I have no access to the standard sources that you mentioned or the class text-books.

Answer 3

1.Niels Bohr
2.Electrons
3.halogens are not metals.they are the most reactive nonemetals.
5.F.O.Cl.
6.the number of electron from left to right increases.as the atomic number increases the number of electrons increases too.

Answer 4

im sure the answer is in your text. i need to block this site on my firewall for my kids computer