Mass number = protons + neutrons = 34+46 =80
the element with an atomic number of 34 and mass number of 80 is selenium
Answer:
An atom gets larger as the number of electronic shells increase; therefore the radius of atoms increases as you go down a certain group in the periodic table of elements. In general, the size of an atom will decrease as you move from left to the right of a certain period.
Explanation:
Answer:
see note under explanation
Explanation:
When describing system and surroundings the system is typically defined as the 'object of interest' being studied and surroundings 'everything else'. In thermodynamics heat flow is typically defined as endothermic or exothermic. However, one should realize that the terms endothermic and exothermic are in reference to the 'system' or object of interest being studied. For example if heat is transferred from a warm object to a cooler object it is imperative that the system be defined 1st. So, with that, assume the system is a warm metal cylinder being added into cooler water. When describing heat flow then the process is exothermic with respect to the metal cylinder (the system) but endothermic to the water and surroundings (everything else).
This is false because males have 1 X and 1 Y chromosome. It's females who have 2 X chromosomes. So, it's false.
Answer:
Explanation:
To calculate their average atomic masses which is otherwise known as the relative atomic mass, we simply multiply the given abundances of the atoms and the given atomic masses.
The abundace is the proportion or percentage or fraction by which each of the isotopes of an element occurs in nature.
This can be expressed below:
RAM = Σmₙαₙ
where mₙ is the mass of isotope n
αₙ is the abundance of isotope n
for this problem:
RAM of Li = m₆α₆ + m₇α₇
m₆ is mass of isotope Li-6
α₆ is the abundance of isotope Li-6
m₇ is mass of isotope Li-7
α₇ is the abundance of isotope Li-7
