4. An ion of iron has an 26 protons, 30 neutrons, and 23 electrons. What are its atomic number, atomic mass, and net charge? O A atomic number = 26, atomic mass - 56, net charge = 3+
O B. atomic number = 26, atomic mass = 56, net charge = 3-
O C. atomic number = 30, atomic mass = 56, net charge = 3+
OD atomic number = 56, atomic mass = 26, net charge = 3-
5. A lithium atom contains 3 protons, 4 neutrons and 3 electrons What would be formed if one proton is added to this atom?

which

what is a measurement of the earth’s history divided into time periods?

> fossil record <

sedimentary rock

> geologic time scale <

radioactive elements

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.