Answer:
A
Explanation:
To label an element correctly using a combination of the symbol, mass number and atomic number furnishes some important information about the element.
We can obtain these information from the element provided that correct labeling of the element is presented. Firstly, after writing the symbol of the element, the atomic number is placed as a subscript on the left while the mass number of the atomic mass is placed as a superscript on the same left.
Looking at the question asked, we have the element symbol in the correct position as Ca, with 42 also in the correct position which is the mass number. The third number which is 20 is thus the atomic number of the element.
Answer : The final temperature of the copper is, 
Solution :
Formula used :
where,
Q = heat gained = 299 cal
m = mass of copper = 52 g
c = specific heat of copper = 
= final temperature = ?
= initial temperature = 
Now put all the given values in the above formula, we get the final temperature of copper.
Therefore, the final temperature of the copper is,
Density = mass/volume = 2000/4000 = 0.5 grams/cm3. Hope this hopes!
Answer:
A bond forms between two non metals is covalent
Explanation:
For example Chlorine Cl is a non metal bond in Cl - Cl is covalent
C protons, elctrons 093939393
