<u>Answer:</u>
<em>B. A and B</em>
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<u>Explanation:</u>
1. Solids have a definite volume, definite size and definite shape
2. The particles present in a solid are very closely packed since the intermolecular forces between them are very strong. The molecules do not move apart.
3. Melting point is the temperature at which solid changes into a liquid.
4. When a solid is heated to the melting point the intermolecular forces are overcome by the energy and the molecules present in it moves from its fixed position to take its liquid state which is called as melting.
Answer:
a. Pb 208
b. About 21.7 minutes
c. only a trace amount
Explanation:
It under goes beta decay.
There should be virtually nothing after an hour
Explanation:
Given elements:
F, Sr, P, Ca, O, Br, Rb, Sb, Li, S
Elements with the same chemical reactivity will belong to the same group on the periodic table. This implies that elements in the same column will have the same reactivity;
Li and Rb are both alkali metals in group 1
Ca and Sr are both alkali earth metals in group 2
F and Br are halogens in group 7
O and S are group 6 elements
P and Sb are both in group 5 on the periodic table
So these groupings show elements with the same chemical properties.
