I believe you may be referring to cold welding? This is when two pieces of metal are put together in a vacuum and are thus permanently "cold-welded" together
Answer:
B
Explanation:
living things are not required to move
Answer:
1 valence - Alkali Metals: Li Lithium, Na Sodium, K Potassium
2 valence - Alkaline Earth Metals: Be Beryllium, Mg Magnesium, Ca Calcium
3 valence - Non-metals: B Boron, Al Aluminium
4 valence - Non-metals: C Carbon, Si Silicon
5 valence - Non-metals: N Nitrogen, P Phosphorus
6 valence - Non-metals: O Oxygen, S Sulfur, Se Selenium
7 valence - Halogens: F Fluorine, Cl Chlorine, Br Bromine
8 valence - Noble Gases: He Helium, Ne Neon, Ar Argon
Answer:
option A is correct ( sodium, calcium and barium)
Explanation:
Given compounds:
Sodium chloride , calcium sulfide, barium oxide
We know that metals form positive ions. In order to solve the problem we must identify the metals from given compounds.
Na⁺Cl⁻
Ca²⁺S²⁻
Ba²⁺O²⁻
We can see that sodium, calcium and barium contain positive charges.
Thus option A is correct.
Because sodium have one valance electron. When it combine with chlorine sodium lose its one electron to complete the octet and chlorine accept it to complete its octet. Thus sodium form positive ion and chlorine form negative ion.
Similarly barium and calcium are present in group 2. Both have two valance electron. When they lose them cation are formed.
Other option are incorrect because,
Option B have sulfur and oxygen which are anion.
Option C have chlorine which is also anion
Option D have chlorine, sulfur and oxygen that are anions.
litmus paper
Because it will just tell if the solution is acidic or basic, it won't tell the pH
