Question

of the elements pt, v, li, and kr, which is a nonmetal?
o a pt
o b v
o c kr
o d li
question 10 (1 point)
to what category of elements does an element belong if it is a poor conductor of electricity?
o a transition elements
o b nonmetals
o c metals
o d metalloids
question 11 (1 point)
in which of the following sets is the symbol of the element, the number of protons, and the number of electrons given correctly?
o a zn, 30 protons, 60 electrons
o b in, 49 protons, 49 electrons
o c cs, 55 protons, 132.9 electrons
o d f, 19 protons, 19 electrons

Explanation:

• Question 9: Platinum (Pt) is a transition metal, vanadium (V) is a transition metal, lithium (Li) is an alkali metal, and krypton (Kr) is a noble gas (non - metal).
• Question 10: Non - metals are generally poor conductors of electricity. Transition elements (metals) are good conductors, metals are good conductors, and metalloids have intermediate conductivity.
• Question 11: For a neutral atom, the number of protons equals the number of electrons.
• In option a, for Zn (zinc), if it has 30 protons, it should have 30 electrons (not 60).
• In option b, for In (indium), with 49 protons, it has 49 electrons (correct as it is a neutral atom).
• In option c, the number of electrons must be an integer. 132.9 is not a valid number of electrons for Cs (cesium) which has 55 protons (a neutral Cs atom has 55 electrons).
• In option d, F (fluorine) has 9 protons (not 19). A neutral F atom has 9 electrons.

Answer:

• Question 9: c. Kr
• Question 10: b. nonmetals
• Question 11: b. In, 49 protons, 49 electrons