The most common form of calcium has 20 protons, 20 nuetrons and 20 electrons. Which of the following element is an isotope of calcium?
a. an atom with 21 protons, 20 neutrons, 21 electrons
b. an atom with 20 protons, 20 neutrons, 18 electrons
c. an atom with 21 protons, 21 neutrons, 21 electrons
d. an atom with 20 protons, 21 neutrons, and 20 electrons
Ans: d. an atom with 20 protons, 21 neutrons, and 20 electrons
You might also like to view...
Sedimentation in bogs and marshes develop ________ soils
A) inorganic B) mineral C) organic D) loamy
Many types of bacteria are only ________ when dispersing from more stable and heterogeneous communities known as biofilms.
Fill in the blank(s) with the appropriate word(s).
All mammals ________.
A. are ectothermic B. have mammary glands and hair C. are nocturnal D. give birth to live young
The ancestors of land plants were probably ________ that lived in ________
A) green algae similar to charophytes; the open ocean B) green algae similar to charophytes; coastal marshes or lake fringes C) cyanobacteria; coastal marshes or lake fringes D) cyanobacteria; moist soil crust communities