Answer:
Only to elements are gases at room temperature and standard pressure.
Fluorine and chlorine.
Explanation:
The group 17 is called halogen.
There are five elements in halogen group.
All halogens required one electrons to complete the octet and to get the noble gas electronic configuration.
All halogen elements have seven valance electrons.
Halogen elements:
Fluorine, chlorine, Bromine, iodine and astatine
Fluorine is gas at room temperature which s 25°C and standard pressure which is 1 atm.
It is present in the from of F₂.
Chlorine is also gas at room temperature and standard pressure.
It is present in the from of Cl₂.
The bromine is liquid under these condition.
Iodine and astatine are solids.
As we move down the group their melting and boiling points increases.
A phospholipid structure is shown in the picture attached. It has three parts: the hydrophobic tail, the hydrophilic head and the phosphate group in the center. Thus, the function of the phosphate group is to link the hydrophobic and hydrophilic parts of a phospholipid. Specifically, the phosphate group is part of the hydrophilic head. So, it is used to connect the phospholipids to polar compounds.
Answer: exactly 82 protons
Explanation:
Since lead has 82 protons the number of neutrons in an atom of lead-204 is 204-82=122. Similarly, lead-206 has 124 neutrons, lead-207 has 125 neutrons and lead-208 has 126 neutrons.
You welcome :)
Answer:
The two ice sheets on Earth today cover most of Greenland and Antarctica. During the last ice age, ice sheets also covered much of North America and Scandinavia. Together, the Antarctic and Greenland ice sheets contain more than 99 percent of the freshwater ice on Earth.
Hope this helps! (:
A beaker of black powder can be a mixture with different substances (i.e gunpowder: a mixture of sulfur, charcoal, etc.), an element which can probably be carbon (known as black), and a compound as well which can be potassium nitrate. Hence, the answer is D.
