Answer:
Magnesium and calcium belong to the second group i. e. alkaline earth metals. They are known as earth metals because they are extracted from the earth. They are very reactive elements. Their reactivity increases when we go from top to bottom because the outermost electrons goes farther from the nucleus i. e. atomic radius increases so less energy is needed for its removal.
Neutrons have no electrical charge.
A ratio of 0.89% w / v or 0.0089 in fraction means that
there is 0.89 weight of NaCl pero volume of solution. Therefore the mass of
NaCl is:
mass NaCl = 0.0089 * 200
<span>mass NaCl = 1.78 grams</span>
Answer:
C. fluorine (F) and chlorine (Cl)
D. arsenic (As) and antimony (Sb)
Explanation:
In the periodic table , all the elements are arranged according to the atomic number ,
and the elements are placed in groups and periods ,
The elements with similar chemical and physical properties are placed in a common group .
The elements present in the same group have the same number of valence electrons in the valence shell .
Hence , from the given options ,
fluorine (F) and chlorine (Cl) belongs to group 17 with 7 valence electrons in the outermost shell .
arsenic (As) and antimony (Sb) belong to group 15 with 3 valence electrons in the outermost shell .
The answer is D. This is because a synthesis reaction is when two elements combined to make a product (ex. A+B= AB). Hope this helps!
