The answer is (4) Ag(s)
Solid Silver has a Face Centered Cubic crystal structure.
The remaining choices are gases (H2 & Ar) and liquid (Br). Liquids and gases do not form crystal structures as their atoms are loose.
You must first know that the number of protons and neutrons are same, and neutrons number may vary. Carbon 12 has 6 protons, 6 neutrons and 6 electrons. Sodium 23 has 12 protons , 12 electrons and and 11 neutrons. Silver 108 has 47 protons, 47 electrons and 61 electrons. Finally, Sulfur 32 has 16 protons, 16 nuetrons and 16 electrons. Basically the number of neutrons in an atom can be found by subtracting proton number from mass number
Hi. You did not provide any response options. However, a PCR reaction proceeds as follows.
After the primers are added to the test tube containing the PCR components. This tube is placed in a device called a thermocycler. At that moment, the stage called denaturation will begin, where the thermocycler increases the temperature to the point of breaking the hydrogen bonds that hold the two strands of DNA together. The thermal cycler increases the temperature up to 96°C.
After that, the second step of the reaction begins. At that moment, the thermal cycler lowers the temperature to 55º - 65ºC, which is the ideal temperature for the primers to be able to attach themselves to the DNA strands, preparing them for the presence of the polymerase.
After that, the thermocycler raises the temperature to 72ºC, which is the ideal temperature for the DNA polymerase to work. At this stage, the DNA polymerase will use the DNA strand and the primer to build a new DNA strand, which will be annealed to the DNA strand used as a template.
These three steps will be repeated about 35 times, generating many copies of DNA.
