Answer:
a. Be and Mg
Explanation:
Be (beryllium) and Mg (magnesium) are both found in the alkaline earth metals family (group 2) on the periodic table. Elements in the same family or group have similar properties,
Ca and Br are in groups 2 and 17
Cl and Ar are in groups 17 and 18
Na and P are in groups 1 and 15
double-displacement reaction
Explanation:
We have the chemical reaction:
Na₂S (aq) + Cd(NO₃)₂ (aq) → CdS (s) + 2 NaNO₃ (aq)
where:
(aq) - aqueous
(s) - solid
This is a double-displacement reaction because the reactants exchange atoms or group of atoms between themselves to form the products. To drive the reaction to the right, one of the products is a precipitate.
Generally we can express the double-displacement reaction as following:
AB + CD → AC + BD
Learn more about:
types of chemical reactions
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Answer:
The correct answer is - scientific law.
Explanation:
A scientific law is an explanation to a well observed phenomenon of the world which is found true every time tested and universal proven fact, but the reason behind the phenomenon and its existence.
To explain the scientific law there will be various explanation that are called scientific theory, however these theories can not be proved.
Thus, the correct answer is - scientific law.
Answer:
1. Lanthanum-139 atom is the stable isotope of lanthanum with relative atomic mass 138.906348, 99.9 atom percent natural abundance and nuclear spin 7/2.
2. In fact, over 80% of electric cars sold globally utilized permanent magnet-based motors in 2019. These magnets are typically made with rare-earth materials such as neodymium and dysprosium, which have a very geographically constrained supply chain.
3. It is the second most reactive of the rare-earth metals after europium. Lanthanum oxidizes in air at room temperature to form La2O3. It slowly reacts with water and quickly dissolves in diluted acids, except hydrofluoric acid (HF) because of formation of a protective fluoride (LaF3) layer on the surface of the metal.
Explanation: