Answer is: beryllium-10.
The diagram shows that atom has 4 protons, 5 neutrons and 2 valence electrons.
Atomic number is the number of protons, which is characteristic of a chemical element, beryllium (Be) is an element with atomic number 4.
Two valence electrons means that atom is from 2. group of periodic table, only beryllium is from that group; sodium (1. group), boron (13. group) and carbon (14. group).
Beryllium-10 has 6 neutrons, so it is isotope (different number of neutrons or mass number).
ANSWER:
Potential energy due to the position of an object above Earth's surface is called gravitational potential energy.
EXPLANATION:
Gravitational energy is the potential energy compared with gravitational force, as work is needed to further things against Earth’s gravity. The potential energy due to high positions is called gravitational potential energy, and is evidenced by water in an elevated storage or kept behind a dam. If an article falls from one point to different point inside a gravitational field, the force of gravitation will do actual work on the object, and the gravitational potential energy will decrease by the same amount.
Answer:
151.1J
Explanation:
Given parameters:
Mass of iron = 6.21g
Initial temperature of iron = 25°C
Final temperature of iron = 79.8°C
Unknown:
Amount of heat = ?
Solution:
The amount of heat require to cause this temperature can be determined using the expression below;
H = m c (T₂ - T₁)
H is the amount of heat
m is the mass
c is the specific heat capacity
T is the temperature
Specific heat capacity of iron 0.444J/g°C
Insert the parameters and solve;
H = 6.21 x 0.444 x (79.8 - 25)
H = 151.1J
Answer : The molecule
is a polar molecule.
Explanation :
Polar molecule : When the arrangement of the molecule is asymmetrical then the molecule is polar.
Non-polar molecule : When the arrangement of the molecule is symmetrical then the molecule is non-polar.
The given molecule is, 
The electronegativities of oxygen and fluorine are different. The molecular geometry of
is bent. As, Fluorine is more elctronegative than the oxygen. So, the arrows putting towards the more electronegative element i.e, fluorine. These arrows do not balance each other. Due to this, the asymmetrical arrangement of these bonds makes the molecule polar.
Hence, the given molecule
is polar.
Answer:
15900
Explanation:
I think hope this helps!! :D