Question

properties of atoms and the periodic table
directions: match the term in column ii with the definition in column i. write the letter of the correct term in the blank at the left.
column i
___1. sum of the number of protons and neutrons in the nucleus
___2. region around the nucleus where the electrons are found
___3. positively charged center of an atom
___4. vertical column in the periodic table
___5. neutral particles in the nucleus of an atom
___6. weighted average mass of the mixture of its isotopes
___7. positively charged particles in an atom
___8. table of the elements arranged according to repeated changes in properties
___9. represents the electrons in the outer energy level of an element
___10. negatively charged particles in an atom
___11. atoms of the same element that have different numbers of neutrons
___12. number of protons in an atoms nucleus
___13. horizontal row in the periodic table
___14. smallest known particle that makes up protons and neutrons
___15. the smallest piece of matter that still retains the properties of the element
___16. developed an early periodic chart
___17. approximately 1.67×10^{-24}g
column ii
a. nucleus
b. electrons
c. protons
d. neutrons
e. quark
f. atomic number
g. mass number
h. isotope
i. average atomic mass
j. electron cloud
k. periodic table
l. atom
m. atomic mass unit
n. group
o. electron dot diagram
p. period
q. dmitri mendeleev

Explanation:

1. The mass number is defined as the sum of protons and neutrons in the nucleus.
2. The electron cloud is the region around the nucleus where electrons are found.
3. The nucleus is the positively - charged center of an atom.
4. A group is a vertical column in the periodic table.
5. Neutrons are neutral particles in the nucleus.
6. The average atomic mass is the weighted average mass of an element's isotopes.
7. Protons are positively - charged particles in an atom.
8. The periodic table is a table of elements arranged by property changes.
9. An electron dot diagram represents outer - level electrons.
10. Electrons are negatively - charged particles in an atom.
11. Isotopes are atoms of the same element with different neutron numbers.
12. The atomic number is the number of protons in a nucleus.
13. A period is a horizontal row in the periodic table.
14. Quarks are the smallest known particles making up protons and neutrons.
15. An atom is the smallest matter piece retaining element properties.
16. Dmitri Mendeleev developed an early periodic chart.
17. An atomic mass unit is approximately \(1.67\times10^{-24}\text{g}\).

Answer:

1. g. mass number
2. j. electron cloud
3. a. nucleus
4. n. group
5. d. neutrons
6. i. average atomic mass
7. c. protons
8. k. periodic table
9. o. electron dot diagram
10. b. electrons
11. h. isotope
12. f. atomic number
13. p. period
14. e. quark
15. l. atom
16. q. Dmitri Mendeleev
17. m. atomic mass unit