January 2016 Chemistry Regents #1-5

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Questions 1-5 Questions 6-10 Questions 11-15 Questions 16-20 Questions 21-25 Questions 26-30 Questions 31-35 Questions 36-40 Questions 41-45 Questions 46-50

Question 51-53 Questions 54-56
 Questions 57-61 Questions 62-65 Questions 66-68 Questions 69-72  Questions 73-75  Questions 76-78  Questions 79-82 Questions 83-85
 

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Questions

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Explanations

1. Which phrase describes the charge and mass of a neutron?

(1) a charge of +1 and no mass

(2) a charge of +1 and an approximate mass of l u.

(3) no charge and no mass

(4) no charge and an approximate mass of l u.

 
4   Neutron       mass = 1amu   no charge   
2. What is the number of electrons in a potassium atom?

(1) 18    (3) 20

(2) 19     (4) 3

2   2-8-8-1  add them up and you get 19 

also the atomic number is protons (and electron in an atom)

atoms are neutral

3. The number of valence electrons in each atom of an element affects the element's

(1) chemical properties     (3) decay mode

(2) number of isotopes      (4) half-life

 
1   valence electrons determine reactivity, bonding ratios...chemical properties

 

4. The nuclides I-131 and I-133 are classified as

(1) isomers of the same element

(2) isomers of Xe-131 and Cs-133

(3) isotopes of the same element

(4) isotopes of Xe-131 and Cs-133

3   isotopes- same number of protons (so same element) different number of neutrons (so different mass number)

5. The elements on the Periodic Table are arranged in order of increasing

(1) mass number

(2) atomic number

(3) number of isotopes

(4) number of valence electrons

2   atomic number....look at periodic table

 

Questions 1-5 Questions 6-10 Questions 11-15 Questions 16-20 Questions 21-25 Questions 26-30 Questions 31-35 Questions 36-40 Questions 41-45 Questions 46-50

Question 51-53 Questions 54-56
 Questions 57-61 Questions 62-65 Questions 66-68 Questions 69-72  Questions 73-75  Questions 76-78  Questions 79-82 Questions 83-85
 

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